modernc.org/cc@v1.0.1/v2/testdata/_sqlite/src/insert.c (about)

     1  /*
     2  ** 2001 September 15
     3  **
     4  ** The author disclaims copyright to this source code.  In place of
     5  ** a legal notice, here is a blessing:
     6  **
     7  **    May you do good and not evil.
     8  **    May you find forgiveness for yourself and forgive others.
     9  **    May you share freely, never taking more than you give.
    10  **
    11  *************************************************************************
    12  ** This file contains C code routines that are called by the parser
    13  ** to handle INSERT statements in SQLite.
    14  */
    15  #include "sqliteInt.h"
    16  
    17  /*
    18  ** Generate code that will 
    19  **
    20  **   (1) acquire a lock for table pTab then
    21  **   (2) open pTab as cursor iCur.
    22  **
    23  ** If pTab is a WITHOUT ROWID table, then it is the PRIMARY KEY index
    24  ** for that table that is actually opened.
    25  */
    26  void sqlite3OpenTable(
    27    Parse *pParse,  /* Generate code into this VDBE */
    28    int iCur,       /* The cursor number of the table */
    29    int iDb,        /* The database index in sqlite3.aDb[] */
    30    Table *pTab,    /* The table to be opened */
    31    int opcode      /* OP_OpenRead or OP_OpenWrite */
    32  ){
    33    Vdbe *v;
    34    assert( !IsVirtual(pTab) );
    35    v = sqlite3GetVdbe(pParse);
    36    assert( opcode==OP_OpenWrite || opcode==OP_OpenRead );
    37    sqlite3TableLock(pParse, iDb, pTab->tnum, 
    38                     (opcode==OP_OpenWrite)?1:0, pTab->zName);
    39    if( HasRowid(pTab) ){
    40      sqlite3VdbeAddOp4Int(v, opcode, iCur, pTab->tnum, iDb, pTab->nCol);
    41      VdbeComment((v, "%s", pTab->zName));
    42    }else{
    43      Index *pPk = sqlite3PrimaryKeyIndex(pTab);
    44      assert( pPk!=0 );
    45      assert( pPk->tnum==pTab->tnum );
    46      sqlite3VdbeAddOp3(v, opcode, iCur, pPk->tnum, iDb);
    47      sqlite3VdbeSetP4KeyInfo(pParse, pPk);
    48      VdbeComment((v, "%s", pTab->zName));
    49    }
    50  }
    51  
    52  /*
    53  ** Return a pointer to the column affinity string associated with index
    54  ** pIdx. A column affinity string has one character for each column in 
    55  ** the table, according to the affinity of the column:
    56  **
    57  **  Character      Column affinity
    58  **  ------------------------------
    59  **  'A'            BLOB
    60  **  'B'            TEXT
    61  **  'C'            NUMERIC
    62  **  'D'            INTEGER
    63  **  'F'            REAL
    64  **
    65  ** An extra 'D' is appended to the end of the string to cover the
    66  ** rowid that appears as the last column in every index.
    67  **
    68  ** Memory for the buffer containing the column index affinity string
    69  ** is managed along with the rest of the Index structure. It will be
    70  ** released when sqlite3DeleteIndex() is called.
    71  */
    72  const char *sqlite3IndexAffinityStr(sqlite3 *db, Index *pIdx){
    73    if( !pIdx->zColAff ){
    74      /* The first time a column affinity string for a particular index is
    75      ** required, it is allocated and populated here. It is then stored as
    76      ** a member of the Index structure for subsequent use.
    77      **
    78      ** The column affinity string will eventually be deleted by
    79      ** sqliteDeleteIndex() when the Index structure itself is cleaned
    80      ** up.
    81      */
    82      int n;
    83      Table *pTab = pIdx->pTable;
    84      pIdx->zColAff = (char *)sqlite3DbMallocRaw(0, pIdx->nColumn+1);
    85      if( !pIdx->zColAff ){
    86        sqlite3OomFault(db);
    87        return 0;
    88      }
    89      for(n=0; n<pIdx->nColumn; n++){
    90        i16 x = pIdx->aiColumn[n];
    91        if( x>=0 ){
    92          pIdx->zColAff[n] = pTab->aCol[x].affinity;
    93        }else if( x==XN_ROWID ){
    94          pIdx->zColAff[n] = SQLITE_AFF_INTEGER;
    95        }else{
    96          char aff;
    97          assert( x==XN_EXPR );
    98          assert( pIdx->aColExpr!=0 );
    99          aff = sqlite3ExprAffinity(pIdx->aColExpr->a[n].pExpr);
   100          if( aff==0 ) aff = SQLITE_AFF_BLOB;
   101          pIdx->zColAff[n] = aff;
   102        }
   103      }
   104      pIdx->zColAff[n] = 0;
   105    }
   106   
   107    return pIdx->zColAff;
   108  }
   109  
   110  /*
   111  ** Compute the affinity string for table pTab, if it has not already been
   112  ** computed.  As an optimization, omit trailing SQLITE_AFF_BLOB affinities.
   113  **
   114  ** If the affinity exists (if it is no entirely SQLITE_AFF_BLOB values) and
   115  ** if iReg>0 then code an OP_Affinity opcode that will set the affinities
   116  ** for register iReg and following.  Or if affinities exists and iReg==0,
   117  ** then just set the P4 operand of the previous opcode (which should  be
   118  ** an OP_MakeRecord) to the affinity string.
   119  **
   120  ** A column affinity string has one character per column:
   121  **
   122  **  Character      Column affinity
   123  **  ------------------------------
   124  **  'A'            BLOB
   125  **  'B'            TEXT
   126  **  'C'            NUMERIC
   127  **  'D'            INTEGER
   128  **  'E'            REAL
   129  */
   130  void sqlite3TableAffinity(Vdbe *v, Table *pTab, int iReg){
   131    int i;
   132    char *zColAff = pTab->zColAff;
   133    if( zColAff==0 ){
   134      sqlite3 *db = sqlite3VdbeDb(v);
   135      zColAff = (char *)sqlite3DbMallocRaw(0, pTab->nCol+1);
   136      if( !zColAff ){
   137        sqlite3OomFault(db);
   138        return;
   139      }
   140  
   141      for(i=0; i<pTab->nCol; i++){
   142        zColAff[i] = pTab->aCol[i].affinity;
   143      }
   144      do{
   145        zColAff[i--] = 0;
   146      }while( i>=0 && zColAff[i]==SQLITE_AFF_BLOB );
   147      pTab->zColAff = zColAff;
   148    }
   149    i = sqlite3Strlen30(zColAff);
   150    if( i ){
   151      if( iReg ){
   152        sqlite3VdbeAddOp4(v, OP_Affinity, iReg, i, 0, zColAff, i);
   153      }else{
   154        sqlite3VdbeChangeP4(v, -1, zColAff, i);
   155      }
   156    }
   157  }
   158  
   159  /*
   160  ** Return non-zero if the table pTab in database iDb or any of its indices
   161  ** have been opened at any point in the VDBE program. This is used to see if 
   162  ** a statement of the form  "INSERT INTO <iDb, pTab> SELECT ..." can 
   163  ** run without using a temporary table for the results of the SELECT. 
   164  */
   165  static int readsTable(Parse *p, int iDb, Table *pTab){
   166    Vdbe *v = sqlite3GetVdbe(p);
   167    int i;
   168    int iEnd = sqlite3VdbeCurrentAddr(v);
   169  #ifndef SQLITE_OMIT_VIRTUALTABLE
   170    VTable *pVTab = IsVirtual(pTab) ? sqlite3GetVTable(p->db, pTab) : 0;
   171  #endif
   172  
   173    for(i=1; i<iEnd; i++){
   174      VdbeOp *pOp = sqlite3VdbeGetOp(v, i);
   175      assert( pOp!=0 );
   176      if( pOp->opcode==OP_OpenRead && pOp->p3==iDb ){
   177        Index *pIndex;
   178        int tnum = pOp->p2;
   179        if( tnum==pTab->tnum ){
   180          return 1;
   181        }
   182        for(pIndex=pTab->pIndex; pIndex; pIndex=pIndex->pNext){
   183          if( tnum==pIndex->tnum ){
   184            return 1;
   185          }
   186        }
   187      }
   188  #ifndef SQLITE_OMIT_VIRTUALTABLE
   189      if( pOp->opcode==OP_VOpen && pOp->p4.pVtab==pVTab ){
   190        assert( pOp->p4.pVtab!=0 );
   191        assert( pOp->p4type==P4_VTAB );
   192        return 1;
   193      }
   194  #endif
   195    }
   196    return 0;
   197  }
   198  
   199  #ifndef SQLITE_OMIT_AUTOINCREMENT
   200  /*
   201  ** Locate or create an AutoincInfo structure associated with table pTab
   202  ** which is in database iDb.  Return the register number for the register
   203  ** that holds the maximum rowid.  Return zero if pTab is not an AUTOINCREMENT
   204  ** table.  (Also return zero when doing a VACUUM since we do not want to
   205  ** update the AUTOINCREMENT counters during a VACUUM.)
   206  **
   207  ** There is at most one AutoincInfo structure per table even if the
   208  ** same table is autoincremented multiple times due to inserts within
   209  ** triggers.  A new AutoincInfo structure is created if this is the
   210  ** first use of table pTab.  On 2nd and subsequent uses, the original
   211  ** AutoincInfo structure is used.
   212  **
   213  ** Three memory locations are allocated:
   214  **
   215  **   (1)  Register to hold the name of the pTab table.
   216  **   (2)  Register to hold the maximum ROWID of pTab.
   217  **   (3)  Register to hold the rowid in sqlite_sequence of pTab
   218  **
   219  ** The 2nd register is the one that is returned.  That is all the
   220  ** insert routine needs to know about.
   221  */
   222  static int autoIncBegin(
   223    Parse *pParse,      /* Parsing context */
   224    int iDb,            /* Index of the database holding pTab */
   225    Table *pTab         /* The table we are writing to */
   226  ){
   227    int memId = 0;      /* Register holding maximum rowid */
   228    if( (pTab->tabFlags & TF_Autoincrement)!=0
   229     && (pParse->db->mDbFlags & DBFLAG_Vacuum)==0
   230    ){
   231      Parse *pToplevel = sqlite3ParseToplevel(pParse);
   232      AutoincInfo *pInfo;
   233  
   234      pInfo = pToplevel->pAinc;
   235      while( pInfo && pInfo->pTab!=pTab ){ pInfo = pInfo->pNext; }
   236      if( pInfo==0 ){
   237        pInfo = sqlite3DbMallocRawNN(pParse->db, sizeof(*pInfo));
   238        if( pInfo==0 ) return 0;
   239        pInfo->pNext = pToplevel->pAinc;
   240        pToplevel->pAinc = pInfo;
   241        pInfo->pTab = pTab;
   242        pInfo->iDb = iDb;
   243        pToplevel->nMem++;                  /* Register to hold name of table */
   244        pInfo->regCtr = ++pToplevel->nMem;  /* Max rowid register */
   245        pToplevel->nMem++;                  /* Rowid in sqlite_sequence */
   246      }
   247      memId = pInfo->regCtr;
   248    }
   249    return memId;
   250  }
   251  
   252  /*
   253  ** This routine generates code that will initialize all of the
   254  ** register used by the autoincrement tracker.  
   255  */
   256  void sqlite3AutoincrementBegin(Parse *pParse){
   257    AutoincInfo *p;            /* Information about an AUTOINCREMENT */
   258    sqlite3 *db = pParse->db;  /* The database connection */
   259    Db *pDb;                   /* Database only autoinc table */
   260    int memId;                 /* Register holding max rowid */
   261    Vdbe *v = pParse->pVdbe;   /* VDBE under construction */
   262  
   263    /* This routine is never called during trigger-generation.  It is
   264    ** only called from the top-level */
   265    assert( pParse->pTriggerTab==0 );
   266    assert( sqlite3IsToplevel(pParse) );
   267  
   268    assert( v );   /* We failed long ago if this is not so */
   269    for(p = pParse->pAinc; p; p = p->pNext){
   270      static const int iLn = VDBE_OFFSET_LINENO(2);
   271      static const VdbeOpList autoInc[] = {
   272        /* 0  */ {OP_Null,    0,  0, 0},
   273        /* 1  */ {OP_Rewind,  0,  9, 0},
   274        /* 2  */ {OP_Column,  0,  0, 0},
   275        /* 3  */ {OP_Ne,      0,  7, 0},
   276        /* 4  */ {OP_Rowid,   0,  0, 0},
   277        /* 5  */ {OP_Column,  0,  1, 0},
   278        /* 6  */ {OP_Goto,    0,  9, 0},
   279        /* 7  */ {OP_Next,    0,  2, 0},
   280        /* 8  */ {OP_Integer, 0,  0, 0},
   281        /* 9  */ {OP_Close,   0,  0, 0} 
   282      };
   283      VdbeOp *aOp;
   284      pDb = &db->aDb[p->iDb];
   285      memId = p->regCtr;
   286      assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
   287      sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenRead);
   288      sqlite3VdbeLoadString(v, memId-1, p->pTab->zName);
   289      aOp = sqlite3VdbeAddOpList(v, ArraySize(autoInc), autoInc, iLn);
   290      if( aOp==0 ) break;
   291      aOp[0].p2 = memId;
   292      aOp[0].p3 = memId+1;
   293      aOp[2].p3 = memId;
   294      aOp[3].p1 = memId-1;
   295      aOp[3].p3 = memId;
   296      aOp[3].p5 = SQLITE_JUMPIFNULL;
   297      aOp[4].p2 = memId+1;
   298      aOp[5].p3 = memId;
   299      aOp[8].p2 = memId;
   300    }
   301  }
   302  
   303  /*
   304  ** Update the maximum rowid for an autoincrement calculation.
   305  **
   306  ** This routine should be called when the regRowid register holds a
   307  ** new rowid that is about to be inserted.  If that new rowid is
   308  ** larger than the maximum rowid in the memId memory cell, then the
   309  ** memory cell is updated.
   310  */
   311  static void autoIncStep(Parse *pParse, int memId, int regRowid){
   312    if( memId>0 ){
   313      sqlite3VdbeAddOp2(pParse->pVdbe, OP_MemMax, memId, regRowid);
   314    }
   315  }
   316  
   317  /*
   318  ** This routine generates the code needed to write autoincrement
   319  ** maximum rowid values back into the sqlite_sequence register.
   320  ** Every statement that might do an INSERT into an autoincrement
   321  ** table (either directly or through triggers) needs to call this
   322  ** routine just before the "exit" code.
   323  */
   324  static SQLITE_NOINLINE void autoIncrementEnd(Parse *pParse){
   325    AutoincInfo *p;
   326    Vdbe *v = pParse->pVdbe;
   327    sqlite3 *db = pParse->db;
   328  
   329    assert( v );
   330    for(p = pParse->pAinc; p; p = p->pNext){
   331      static const int iLn = VDBE_OFFSET_LINENO(2);
   332      static const VdbeOpList autoIncEnd[] = {
   333        /* 0 */ {OP_NotNull,     0, 2, 0},
   334        /* 1 */ {OP_NewRowid,    0, 0, 0},
   335        /* 2 */ {OP_MakeRecord,  0, 2, 0},
   336        /* 3 */ {OP_Insert,      0, 0, 0},
   337        /* 4 */ {OP_Close,       0, 0, 0}
   338      };
   339      VdbeOp *aOp;
   340      Db *pDb = &db->aDb[p->iDb];
   341      int iRec;
   342      int memId = p->regCtr;
   343  
   344      iRec = sqlite3GetTempReg(pParse);
   345      assert( sqlite3SchemaMutexHeld(db, 0, pDb->pSchema) );
   346      sqlite3OpenTable(pParse, 0, p->iDb, pDb->pSchema->pSeqTab, OP_OpenWrite);
   347      aOp = sqlite3VdbeAddOpList(v, ArraySize(autoIncEnd), autoIncEnd, iLn);
   348      if( aOp==0 ) break;
   349      aOp[0].p1 = memId+1;
   350      aOp[1].p2 = memId+1;
   351      aOp[2].p1 = memId-1;
   352      aOp[2].p3 = iRec;
   353      aOp[3].p2 = iRec;
   354      aOp[3].p3 = memId+1;
   355      aOp[3].p5 = OPFLAG_APPEND;
   356      sqlite3ReleaseTempReg(pParse, iRec);
   357    }
   358  }
   359  void sqlite3AutoincrementEnd(Parse *pParse){
   360    if( pParse->pAinc ) autoIncrementEnd(pParse);
   361  }
   362  #else
   363  /*
   364  ** If SQLITE_OMIT_AUTOINCREMENT is defined, then the three routines
   365  ** above are all no-ops
   366  */
   367  # define autoIncBegin(A,B,C) (0)
   368  # define autoIncStep(A,B,C)
   369  #endif /* SQLITE_OMIT_AUTOINCREMENT */
   370  
   371  
   372  /* Forward declaration */
   373  static int xferOptimization(
   374    Parse *pParse,        /* Parser context */
   375    Table *pDest,         /* The table we are inserting into */
   376    Select *pSelect,      /* A SELECT statement to use as the data source */
   377    int onError,          /* How to handle constraint errors */
   378    int iDbDest           /* The database of pDest */
   379  );
   380  
   381  /*
   382  ** This routine is called to handle SQL of the following forms:
   383  **
   384  **    insert into TABLE (IDLIST) values(EXPRLIST),(EXPRLIST),...
   385  **    insert into TABLE (IDLIST) select
   386  **    insert into TABLE (IDLIST) default values
   387  **
   388  ** The IDLIST following the table name is always optional.  If omitted,
   389  ** then a list of all (non-hidden) columns for the table is substituted.
   390  ** The IDLIST appears in the pColumn parameter.  pColumn is NULL if IDLIST
   391  ** is omitted.
   392  **
   393  ** For the pSelect parameter holds the values to be inserted for the
   394  ** first two forms shown above.  A VALUES clause is really just short-hand
   395  ** for a SELECT statement that omits the FROM clause and everything else
   396  ** that follows.  If the pSelect parameter is NULL, that means that the
   397  ** DEFAULT VALUES form of the INSERT statement is intended.
   398  **
   399  ** The code generated follows one of four templates.  For a simple
   400  ** insert with data coming from a single-row VALUES clause, the code executes
   401  ** once straight down through.  Pseudo-code follows (we call this
   402  ** the "1st template"):
   403  **
   404  **         open write cursor to <table> and its indices
   405  **         put VALUES clause expressions into registers
   406  **         write the resulting record into <table>
   407  **         cleanup
   408  **
   409  ** The three remaining templates assume the statement is of the form
   410  **
   411  **   INSERT INTO <table> SELECT ...
   412  **
   413  ** If the SELECT clause is of the restricted form "SELECT * FROM <table2>" -
   414  ** in other words if the SELECT pulls all columns from a single table
   415  ** and there is no WHERE or LIMIT or GROUP BY or ORDER BY clauses, and
   416  ** if <table2> and <table1> are distinct tables but have identical
   417  ** schemas, including all the same indices, then a special optimization
   418  ** is invoked that copies raw records from <table2> over to <table1>.
   419  ** See the xferOptimization() function for the implementation of this
   420  ** template.  This is the 2nd template.
   421  **
   422  **         open a write cursor to <table>
   423  **         open read cursor on <table2>
   424  **         transfer all records in <table2> over to <table>
   425  **         close cursors
   426  **         foreach index on <table>
   427  **           open a write cursor on the <table> index
   428  **           open a read cursor on the corresponding <table2> index
   429  **           transfer all records from the read to the write cursors
   430  **           close cursors
   431  **         end foreach
   432  **
   433  ** The 3rd template is for when the second template does not apply
   434  ** and the SELECT clause does not read from <table> at any time.
   435  ** The generated code follows this template:
   436  **
   437  **         X <- A
   438  **         goto B
   439  **      A: setup for the SELECT
   440  **         loop over the rows in the SELECT
   441  **           load values into registers R..R+n
   442  **           yield X
   443  **         end loop
   444  **         cleanup after the SELECT
   445  **         end-coroutine X
   446  **      B: open write cursor to <table> and its indices
   447  **      C: yield X, at EOF goto D
   448  **         insert the select result into <table> from R..R+n
   449  **         goto C
   450  **      D: cleanup
   451  **
   452  ** The 4th template is used if the insert statement takes its
   453  ** values from a SELECT but the data is being inserted into a table
   454  ** that is also read as part of the SELECT.  In the third form,
   455  ** we have to use an intermediate table to store the results of
   456  ** the select.  The template is like this:
   457  **
   458  **         X <- A
   459  **         goto B
   460  **      A: setup for the SELECT
   461  **         loop over the tables in the SELECT
   462  **           load value into register R..R+n
   463  **           yield X
   464  **         end loop
   465  **         cleanup after the SELECT
   466  **         end co-routine R
   467  **      B: open temp table
   468  **      L: yield X, at EOF goto M
   469  **         insert row from R..R+n into temp table
   470  **         goto L
   471  **      M: open write cursor to <table> and its indices
   472  **         rewind temp table
   473  **      C: loop over rows of intermediate table
   474  **           transfer values form intermediate table into <table>
   475  **         end loop
   476  **      D: cleanup
   477  */
   478  void sqlite3Insert(
   479    Parse *pParse,        /* Parser context */
   480    SrcList *pTabList,    /* Name of table into which we are inserting */
   481    Select *pSelect,      /* A SELECT statement to use as the data source */
   482    IdList *pColumn,      /* Column names corresponding to IDLIST. */
   483    int onError           /* How to handle constraint errors */
   484  ){
   485    sqlite3 *db;          /* The main database structure */
   486    Table *pTab;          /* The table to insert into.  aka TABLE */
   487    int i, j;             /* Loop counters */
   488    Vdbe *v;              /* Generate code into this virtual machine */
   489    Index *pIdx;          /* For looping over indices of the table */
   490    int nColumn;          /* Number of columns in the data */
   491    int nHidden = 0;      /* Number of hidden columns if TABLE is virtual */
   492    int iDataCur = 0;     /* VDBE cursor that is the main data repository */
   493    int iIdxCur = 0;      /* First index cursor */
   494    int ipkColumn = -1;   /* Column that is the INTEGER PRIMARY KEY */
   495    int endOfLoop;        /* Label for the end of the insertion loop */
   496    int srcTab = 0;       /* Data comes from this temporary cursor if >=0 */
   497    int addrInsTop = 0;   /* Jump to label "D" */
   498    int addrCont = 0;     /* Top of insert loop. Label "C" in templates 3 and 4 */
   499    SelectDest dest;      /* Destination for SELECT on rhs of INSERT */
   500    int iDb;              /* Index of database holding TABLE */
   501    u8 useTempTable = 0;  /* Store SELECT results in intermediate table */
   502    u8 appendFlag = 0;    /* True if the insert is likely to be an append */
   503    u8 withoutRowid;      /* 0 for normal table.  1 for WITHOUT ROWID table */
   504    u8 bIdListInOrder;    /* True if IDLIST is in table order */
   505    ExprList *pList = 0;  /* List of VALUES() to be inserted  */
   506  
   507    /* Register allocations */
   508    int regFromSelect = 0;/* Base register for data coming from SELECT */
   509    int regAutoinc = 0;   /* Register holding the AUTOINCREMENT counter */
   510    int regRowCount = 0;  /* Memory cell used for the row counter */
   511    int regIns;           /* Block of regs holding rowid+data being inserted */
   512    int regRowid;         /* registers holding insert rowid */
   513    int regData;          /* register holding first column to insert */
   514    int *aRegIdx = 0;     /* One register allocated to each index */
   515  
   516  #ifndef SQLITE_OMIT_TRIGGER
   517    int isView;                 /* True if attempting to insert into a view */
   518    Trigger *pTrigger;          /* List of triggers on pTab, if required */
   519    int tmask;                  /* Mask of trigger times */
   520  #endif
   521  
   522    db = pParse->db;
   523    if( pParse->nErr || db->mallocFailed ){
   524      goto insert_cleanup;
   525    }
   526    dest.iSDParm = 0;  /* Suppress a harmless compiler warning */
   527  
   528    /* If the Select object is really just a simple VALUES() list with a
   529    ** single row (the common case) then keep that one row of values
   530    ** and discard the other (unused) parts of the pSelect object
   531    */
   532    if( pSelect && (pSelect->selFlags & SF_Values)!=0 && pSelect->pPrior==0 ){
   533      pList = pSelect->pEList;
   534      pSelect->pEList = 0;
   535      sqlite3SelectDelete(db, pSelect);
   536      pSelect = 0;
   537    }
   538  
   539    /* Locate the table into which we will be inserting new information.
   540    */
   541    assert( pTabList->nSrc==1 );
   542    pTab = sqlite3SrcListLookup(pParse, pTabList);
   543    if( pTab==0 ){
   544      goto insert_cleanup;
   545    }
   546    iDb = sqlite3SchemaToIndex(db, pTab->pSchema);
   547    assert( iDb<db->nDb );
   548    if( sqlite3AuthCheck(pParse, SQLITE_INSERT, pTab->zName, 0,
   549                         db->aDb[iDb].zDbSName) ){
   550      goto insert_cleanup;
   551    }
   552    withoutRowid = !HasRowid(pTab);
   553  
   554    /* Figure out if we have any triggers and if the table being
   555    ** inserted into is a view
   556    */
   557  #ifndef SQLITE_OMIT_TRIGGER
   558    pTrigger = sqlite3TriggersExist(pParse, pTab, TK_INSERT, 0, &tmask);
   559    isView = pTab->pSelect!=0;
   560  #else
   561  # define pTrigger 0
   562  # define tmask 0
   563  # define isView 0
   564  #endif
   565  #ifdef SQLITE_OMIT_VIEW
   566  # undef isView
   567  # define isView 0
   568  #endif
   569    assert( (pTrigger && tmask) || (pTrigger==0 && tmask==0) );
   570  
   571    /* If pTab is really a view, make sure it has been initialized.
   572    ** ViewGetColumnNames() is a no-op if pTab is not a view.
   573    */
   574    if( sqlite3ViewGetColumnNames(pParse, pTab) ){
   575      goto insert_cleanup;
   576    }
   577  
   578    /* Cannot insert into a read-only table.
   579    */
   580    if( sqlite3IsReadOnly(pParse, pTab, tmask) ){
   581      goto insert_cleanup;
   582    }
   583  
   584    /* Allocate a VDBE
   585    */
   586    v = sqlite3GetVdbe(pParse);
   587    if( v==0 ) goto insert_cleanup;
   588    if( pParse->nested==0 ) sqlite3VdbeCountChanges(v);
   589    sqlite3BeginWriteOperation(pParse, pSelect || pTrigger, iDb);
   590  
   591  #ifndef SQLITE_OMIT_XFER_OPT
   592    /* If the statement is of the form
   593    **
   594    **       INSERT INTO <table1> SELECT * FROM <table2>;
   595    **
   596    ** Then special optimizations can be applied that make the transfer
   597    ** very fast and which reduce fragmentation of indices.
   598    **
   599    ** This is the 2nd template.
   600    */
   601    if( pColumn==0 && xferOptimization(pParse, pTab, pSelect, onError, iDb) ){
   602      assert( !pTrigger );
   603      assert( pList==0 );
   604      goto insert_end;
   605    }
   606  #endif /* SQLITE_OMIT_XFER_OPT */
   607  
   608    /* If this is an AUTOINCREMENT table, look up the sequence number in the
   609    ** sqlite_sequence table and store it in memory cell regAutoinc.
   610    */
   611    regAutoinc = autoIncBegin(pParse, iDb, pTab);
   612  
   613    /* Allocate registers for holding the rowid of the new row,
   614    ** the content of the new row, and the assembled row record.
   615    */
   616    regRowid = regIns = pParse->nMem+1;
   617    pParse->nMem += pTab->nCol + 1;
   618    if( IsVirtual(pTab) ){
   619      regRowid++;
   620      pParse->nMem++;
   621    }
   622    regData = regRowid+1;
   623  
   624    /* If the INSERT statement included an IDLIST term, then make sure
   625    ** all elements of the IDLIST really are columns of the table and 
   626    ** remember the column indices.
   627    **
   628    ** If the table has an INTEGER PRIMARY KEY column and that column
   629    ** is named in the IDLIST, then record in the ipkColumn variable
   630    ** the index into IDLIST of the primary key column.  ipkColumn is
   631    ** the index of the primary key as it appears in IDLIST, not as
   632    ** is appears in the original table.  (The index of the INTEGER
   633    ** PRIMARY KEY in the original table is pTab->iPKey.)
   634    */
   635    bIdListInOrder = (pTab->tabFlags & TF_OOOHidden)==0;
   636    if( pColumn ){
   637      for(i=0; i<pColumn->nId; i++){
   638        pColumn->a[i].idx = -1;
   639      }
   640      for(i=0; i<pColumn->nId; i++){
   641        for(j=0; j<pTab->nCol; j++){
   642          if( sqlite3StrICmp(pColumn->a[i].zName, pTab->aCol[j].zName)==0 ){
   643            pColumn->a[i].idx = j;
   644            if( i!=j ) bIdListInOrder = 0;
   645            if( j==pTab->iPKey ){
   646              ipkColumn = i;  assert( !withoutRowid );
   647            }
   648            break;
   649          }
   650        }
   651        if( j>=pTab->nCol ){
   652          if( sqlite3IsRowid(pColumn->a[i].zName) && !withoutRowid ){
   653            ipkColumn = i;
   654            bIdListInOrder = 0;
   655          }else{
   656            sqlite3ErrorMsg(pParse, "table %S has no column named %s",
   657                pTabList, 0, pColumn->a[i].zName);
   658            pParse->checkSchema = 1;
   659            goto insert_cleanup;
   660          }
   661        }
   662      }
   663    }
   664  
   665    /* Figure out how many columns of data are supplied.  If the data
   666    ** is coming from a SELECT statement, then generate a co-routine that
   667    ** produces a single row of the SELECT on each invocation.  The
   668    ** co-routine is the common header to the 3rd and 4th templates.
   669    */
   670    if( pSelect ){
   671      /* Data is coming from a SELECT or from a multi-row VALUES clause.
   672      ** Generate a co-routine to run the SELECT. */
   673      int regYield;       /* Register holding co-routine entry-point */
   674      int addrTop;        /* Top of the co-routine */
   675      int rc;             /* Result code */
   676  
   677      regYield = ++pParse->nMem;
   678      addrTop = sqlite3VdbeCurrentAddr(v) + 1;
   679      sqlite3VdbeAddOp3(v, OP_InitCoroutine, regYield, 0, addrTop);
   680      sqlite3SelectDestInit(&dest, SRT_Coroutine, regYield);
   681      dest.iSdst = bIdListInOrder ? regData : 0;
   682      dest.nSdst = pTab->nCol;
   683      rc = sqlite3Select(pParse, pSelect, &dest);
   684      regFromSelect = dest.iSdst;
   685      if( rc || db->mallocFailed || pParse->nErr ) goto insert_cleanup;
   686      sqlite3VdbeEndCoroutine(v, regYield);
   687      sqlite3VdbeJumpHere(v, addrTop - 1);                       /* label B: */
   688      assert( pSelect->pEList );
   689      nColumn = pSelect->pEList->nExpr;
   690  
   691      /* Set useTempTable to TRUE if the result of the SELECT statement
   692      ** should be written into a temporary table (template 4).  Set to
   693      ** FALSE if each output row of the SELECT can be written directly into
   694      ** the destination table (template 3).
   695      **
   696      ** A temp table must be used if the table being updated is also one
   697      ** of the tables being read by the SELECT statement.  Also use a 
   698      ** temp table in the case of row triggers.
   699      */
   700      if( pTrigger || readsTable(pParse, iDb, pTab) ){
   701        useTempTable = 1;
   702      }
   703  
   704      if( useTempTable ){
   705        /* Invoke the coroutine to extract information from the SELECT
   706        ** and add it to a transient table srcTab.  The code generated
   707        ** here is from the 4th template:
   708        **
   709        **      B: open temp table
   710        **      L: yield X, goto M at EOF
   711        **         insert row from R..R+n into temp table
   712        **         goto L
   713        **      M: ...
   714        */
   715        int regRec;          /* Register to hold packed record */
   716        int regTempRowid;    /* Register to hold temp table ROWID */
   717        int addrL;           /* Label "L" */
   718  
   719        srcTab = pParse->nTab++;
   720        regRec = sqlite3GetTempReg(pParse);
   721        regTempRowid = sqlite3GetTempReg(pParse);
   722        sqlite3VdbeAddOp2(v, OP_OpenEphemeral, srcTab, nColumn);
   723        addrL = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm); VdbeCoverage(v);
   724        sqlite3VdbeAddOp3(v, OP_MakeRecord, regFromSelect, nColumn, regRec);
   725        sqlite3VdbeAddOp2(v, OP_NewRowid, srcTab, regTempRowid);
   726        sqlite3VdbeAddOp3(v, OP_Insert, srcTab, regRec, regTempRowid);
   727        sqlite3VdbeGoto(v, addrL);
   728        sqlite3VdbeJumpHere(v, addrL);
   729        sqlite3ReleaseTempReg(pParse, regRec);
   730        sqlite3ReleaseTempReg(pParse, regTempRowid);
   731      }
   732    }else{
   733      /* This is the case if the data for the INSERT is coming from a 
   734      ** single-row VALUES clause
   735      */
   736      NameContext sNC;
   737      memset(&sNC, 0, sizeof(sNC));
   738      sNC.pParse = pParse;
   739      srcTab = -1;
   740      assert( useTempTable==0 );
   741      if( pList ){
   742        nColumn = pList->nExpr;
   743        if( sqlite3ResolveExprListNames(&sNC, pList) ){
   744          goto insert_cleanup;
   745        }
   746      }else{
   747        nColumn = 0;
   748      }
   749    }
   750  
   751    /* If there is no IDLIST term but the table has an integer primary
   752    ** key, the set the ipkColumn variable to the integer primary key 
   753    ** column index in the original table definition.
   754    */
   755    if( pColumn==0 && nColumn>0 ){
   756      ipkColumn = pTab->iPKey;
   757    }
   758  
   759    /* Make sure the number of columns in the source data matches the number
   760    ** of columns to be inserted into the table.
   761    */
   762    for(i=0; i<pTab->nCol; i++){
   763      nHidden += (IsHiddenColumn(&pTab->aCol[i]) ? 1 : 0);
   764    }
   765    if( pColumn==0 && nColumn && nColumn!=(pTab->nCol-nHidden) ){
   766      sqlite3ErrorMsg(pParse, 
   767         "table %S has %d columns but %d values were supplied",
   768         pTabList, 0, pTab->nCol-nHidden, nColumn);
   769      goto insert_cleanup;
   770    }
   771    if( pColumn!=0 && nColumn!=pColumn->nId ){
   772      sqlite3ErrorMsg(pParse, "%d values for %d columns", nColumn, pColumn->nId);
   773      goto insert_cleanup;
   774    }
   775      
   776    /* Initialize the count of rows to be inserted
   777    */
   778    if( db->flags & SQLITE_CountRows ){
   779      regRowCount = ++pParse->nMem;
   780      sqlite3VdbeAddOp2(v, OP_Integer, 0, regRowCount);
   781    }
   782  
   783    /* If this is not a view, open the table and and all indices */
   784    if( !isView ){
   785      int nIdx;
   786      nIdx = sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenWrite, 0, -1, 0,
   787                                        &iDataCur, &iIdxCur);
   788      aRegIdx = sqlite3DbMallocRawNN(db, sizeof(int)*(nIdx+1));
   789      if( aRegIdx==0 ){
   790        goto insert_cleanup;
   791      }
   792      for(i=0, pIdx=pTab->pIndex; i<nIdx; pIdx=pIdx->pNext, i++){
   793        assert( pIdx );
   794        aRegIdx[i] = ++pParse->nMem;
   795        pParse->nMem += pIdx->nColumn;
   796      }
   797    }
   798  
   799    /* This is the top of the main insertion loop */
   800    if( useTempTable ){
   801      /* This block codes the top of loop only.  The complete loop is the
   802      ** following pseudocode (template 4):
   803      **
   804      **         rewind temp table, if empty goto D
   805      **      C: loop over rows of intermediate table
   806      **           transfer values form intermediate table into <table>
   807      **         end loop
   808      **      D: ...
   809      */
   810      addrInsTop = sqlite3VdbeAddOp1(v, OP_Rewind, srcTab); VdbeCoverage(v);
   811      addrCont = sqlite3VdbeCurrentAddr(v);
   812    }else if( pSelect ){
   813      /* This block codes the top of loop only.  The complete loop is the
   814      ** following pseudocode (template 3):
   815      **
   816      **      C: yield X, at EOF goto D
   817      **         insert the select result into <table> from R..R+n
   818      **         goto C
   819      **      D: ...
   820      */
   821      addrInsTop = addrCont = sqlite3VdbeAddOp1(v, OP_Yield, dest.iSDParm);
   822      VdbeCoverage(v);
   823    }
   824  
   825    /* Run the BEFORE and INSTEAD OF triggers, if there are any
   826    */
   827    endOfLoop = sqlite3VdbeMakeLabel(v);
   828    if( tmask & TRIGGER_BEFORE ){
   829      int regCols = sqlite3GetTempRange(pParse, pTab->nCol+1);
   830  
   831      /* build the NEW.* reference row.  Note that if there is an INTEGER
   832      ** PRIMARY KEY into which a NULL is being inserted, that NULL will be
   833      ** translated into a unique ID for the row.  But on a BEFORE trigger,
   834      ** we do not know what the unique ID will be (because the insert has
   835      ** not happened yet) so we substitute a rowid of -1
   836      */
   837      if( ipkColumn<0 ){
   838        sqlite3VdbeAddOp2(v, OP_Integer, -1, regCols);
   839      }else{
   840        int addr1;
   841        assert( !withoutRowid );
   842        if( useTempTable ){
   843          sqlite3VdbeAddOp3(v, OP_Column, srcTab, ipkColumn, regCols);
   844        }else{
   845          assert( pSelect==0 );  /* Otherwise useTempTable is true */
   846          sqlite3ExprCode(pParse, pList->a[ipkColumn].pExpr, regCols);
   847        }
   848        addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, regCols); VdbeCoverage(v);
   849        sqlite3VdbeAddOp2(v, OP_Integer, -1, regCols);
   850        sqlite3VdbeJumpHere(v, addr1);
   851        sqlite3VdbeAddOp1(v, OP_MustBeInt, regCols); VdbeCoverage(v);
   852      }
   853  
   854      /* Cannot have triggers on a virtual table. If it were possible,
   855      ** this block would have to account for hidden column.
   856      */
   857      assert( !IsVirtual(pTab) );
   858  
   859      /* Create the new column data
   860      */
   861      for(i=j=0; i<pTab->nCol; i++){
   862        if( pColumn ){
   863          for(j=0; j<pColumn->nId; j++){
   864            if( pColumn->a[j].idx==i ) break;
   865          }
   866        }
   867        if( (!useTempTable && !pList) || (pColumn && j>=pColumn->nId)
   868              || (pColumn==0 && IsOrdinaryHiddenColumn(&pTab->aCol[i])) ){
   869          sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, regCols+i+1);
   870        }else if( useTempTable ){
   871          sqlite3VdbeAddOp3(v, OP_Column, srcTab, j, regCols+i+1); 
   872        }else{
   873          assert( pSelect==0 ); /* Otherwise useTempTable is true */
   874          sqlite3ExprCodeAndCache(pParse, pList->a[j].pExpr, regCols+i+1);
   875        }
   876        if( pColumn==0 && !IsOrdinaryHiddenColumn(&pTab->aCol[i]) ) j++;
   877      }
   878  
   879      /* If this is an INSERT on a view with an INSTEAD OF INSERT trigger,
   880      ** do not attempt any conversions before assembling the record.
   881      ** If this is a real table, attempt conversions as required by the
   882      ** table column affinities.
   883      */
   884      if( !isView ){
   885        sqlite3TableAffinity(v, pTab, regCols+1);
   886      }
   887  
   888      /* Fire BEFORE or INSTEAD OF triggers */
   889      sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_BEFORE, 
   890          pTab, regCols-pTab->nCol-1, onError, endOfLoop);
   891  
   892      sqlite3ReleaseTempRange(pParse, regCols, pTab->nCol+1);
   893    }
   894  
   895    /* Compute the content of the next row to insert into a range of
   896    ** registers beginning at regIns.
   897    */
   898    if( !isView ){
   899      if( IsVirtual(pTab) ){
   900        /* The row that the VUpdate opcode will delete: none */
   901        sqlite3VdbeAddOp2(v, OP_Null, 0, regIns);
   902      }
   903      if( ipkColumn>=0 ){
   904        if( useTempTable ){
   905          sqlite3VdbeAddOp3(v, OP_Column, srcTab, ipkColumn, regRowid);
   906        }else if( pSelect ){
   907          sqlite3VdbeAddOp2(v, OP_Copy, regFromSelect+ipkColumn, regRowid);
   908        }else{
   909          VdbeOp *pOp;
   910          sqlite3ExprCode(pParse, pList->a[ipkColumn].pExpr, regRowid);
   911          pOp = sqlite3VdbeGetOp(v, -1);
   912          if( ALWAYS(pOp) && pOp->opcode==OP_Null && !IsVirtual(pTab) ){
   913            appendFlag = 1;
   914            pOp->opcode = OP_NewRowid;
   915            pOp->p1 = iDataCur;
   916            pOp->p2 = regRowid;
   917            pOp->p3 = regAutoinc;
   918          }
   919        }
   920        /* If the PRIMARY KEY expression is NULL, then use OP_NewRowid
   921        ** to generate a unique primary key value.
   922        */
   923        if( !appendFlag ){
   924          int addr1;
   925          if( !IsVirtual(pTab) ){
   926            addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, regRowid); VdbeCoverage(v);
   927            sqlite3VdbeAddOp3(v, OP_NewRowid, iDataCur, regRowid, regAutoinc);
   928            sqlite3VdbeJumpHere(v, addr1);
   929          }else{
   930            addr1 = sqlite3VdbeCurrentAddr(v);
   931            sqlite3VdbeAddOp2(v, OP_IsNull, regRowid, addr1+2); VdbeCoverage(v);
   932          }
   933          sqlite3VdbeAddOp1(v, OP_MustBeInt, regRowid); VdbeCoverage(v);
   934        }
   935      }else if( IsVirtual(pTab) || withoutRowid ){
   936        sqlite3VdbeAddOp2(v, OP_Null, 0, regRowid);
   937      }else{
   938        sqlite3VdbeAddOp3(v, OP_NewRowid, iDataCur, regRowid, regAutoinc);
   939        appendFlag = 1;
   940      }
   941      autoIncStep(pParse, regAutoinc, regRowid);
   942  
   943      /* Compute data for all columns of the new entry, beginning
   944      ** with the first column.
   945      */
   946      nHidden = 0;
   947      for(i=0; i<pTab->nCol; i++){
   948        int iRegStore = regRowid+1+i;
   949        if( i==pTab->iPKey ){
   950          /* The value of the INTEGER PRIMARY KEY column is always a NULL.
   951          ** Whenever this column is read, the rowid will be substituted
   952          ** in its place.  Hence, fill this column with a NULL to avoid
   953          ** taking up data space with information that will never be used.
   954          ** As there may be shallow copies of this value, make it a soft-NULL */
   955          sqlite3VdbeAddOp1(v, OP_SoftNull, iRegStore);
   956          continue;
   957        }
   958        if( pColumn==0 ){
   959          if( IsHiddenColumn(&pTab->aCol[i]) ){
   960            j = -1;
   961            nHidden++;
   962          }else{
   963            j = i - nHidden;
   964          }
   965        }else{
   966          for(j=0; j<pColumn->nId; j++){
   967            if( pColumn->a[j].idx==i ) break;
   968          }
   969        }
   970        if( j<0 || nColumn==0 || (pColumn && j>=pColumn->nId) ){
   971          sqlite3ExprCodeFactorable(pParse, pTab->aCol[i].pDflt, iRegStore);
   972        }else if( useTempTable ){
   973          sqlite3VdbeAddOp3(v, OP_Column, srcTab, j, iRegStore); 
   974        }else if( pSelect ){
   975          if( regFromSelect!=regData ){
   976            sqlite3VdbeAddOp2(v, OP_SCopy, regFromSelect+j, iRegStore);
   977          }
   978        }else{
   979          sqlite3ExprCode(pParse, pList->a[j].pExpr, iRegStore);
   980        }
   981      }
   982  
   983      /* Generate code to check constraints and generate index keys and
   984      ** do the insertion.
   985      */
   986  #ifndef SQLITE_OMIT_VIRTUALTABLE
   987      if( IsVirtual(pTab) ){
   988        const char *pVTab = (const char *)sqlite3GetVTable(db, pTab);
   989        sqlite3VtabMakeWritable(pParse, pTab);
   990        sqlite3VdbeAddOp4(v, OP_VUpdate, 1, pTab->nCol+2, regIns, pVTab, P4_VTAB);
   991        sqlite3VdbeChangeP5(v, onError==OE_Default ? OE_Abort : onError);
   992        sqlite3MayAbort(pParse);
   993      }else
   994  #endif
   995      {
   996        int isReplace;    /* Set to true if constraints may cause a replace */
   997        int bUseSeek;     /* True to use OPFLAG_SEEKRESULT */
   998        sqlite3GenerateConstraintChecks(pParse, pTab, aRegIdx, iDataCur, iIdxCur,
   999            regIns, 0, ipkColumn>=0, onError, endOfLoop, &isReplace, 0
  1000        );
  1001        sqlite3FkCheck(pParse, pTab, 0, regIns, 0, 0);
  1002  
  1003        /* Set the OPFLAG_USESEEKRESULT flag if either (a) there are no REPLACE
  1004        ** constraints or (b) there are no triggers and this table is not a
  1005        ** parent table in a foreign key constraint. It is safe to set the
  1006        ** flag in the second case as if any REPLACE constraint is hit, an
  1007        ** OP_Delete or OP_IdxDelete instruction will be executed on each 
  1008        ** cursor that is disturbed. And these instructions both clear the
  1009        ** VdbeCursor.seekResult variable, disabling the OPFLAG_USESEEKRESULT
  1010        ** functionality.  */
  1011        bUseSeek = (isReplace==0 || (pTrigger==0 &&
  1012            ((db->flags & SQLITE_ForeignKeys)==0 || sqlite3FkReferences(pTab)==0)
  1013        ));
  1014        sqlite3CompleteInsertion(pParse, pTab, iDataCur, iIdxCur,
  1015            regIns, aRegIdx, 0, appendFlag, bUseSeek
  1016        );
  1017      }
  1018    }
  1019  
  1020    /* Update the count of rows that are inserted
  1021    */
  1022    if( (db->flags & SQLITE_CountRows)!=0 ){
  1023      sqlite3VdbeAddOp2(v, OP_AddImm, regRowCount, 1);
  1024    }
  1025  
  1026    if( pTrigger ){
  1027      /* Code AFTER triggers */
  1028      sqlite3CodeRowTrigger(pParse, pTrigger, TK_INSERT, 0, TRIGGER_AFTER, 
  1029          pTab, regData-2-pTab->nCol, onError, endOfLoop);
  1030    }
  1031  
  1032    /* The bottom of the main insertion loop, if the data source
  1033    ** is a SELECT statement.
  1034    */
  1035    sqlite3VdbeResolveLabel(v, endOfLoop);
  1036    if( useTempTable ){
  1037      sqlite3VdbeAddOp2(v, OP_Next, srcTab, addrCont); VdbeCoverage(v);
  1038      sqlite3VdbeJumpHere(v, addrInsTop);
  1039      sqlite3VdbeAddOp1(v, OP_Close, srcTab);
  1040    }else if( pSelect ){
  1041      sqlite3VdbeGoto(v, addrCont);
  1042      sqlite3VdbeJumpHere(v, addrInsTop);
  1043    }
  1044  
  1045  insert_end:
  1046    /* Update the sqlite_sequence table by storing the content of the
  1047    ** maximum rowid counter values recorded while inserting into
  1048    ** autoincrement tables.
  1049    */
  1050    if( pParse->nested==0 && pParse->pTriggerTab==0 ){
  1051      sqlite3AutoincrementEnd(pParse);
  1052    }
  1053  
  1054    /*
  1055    ** Return the number of rows inserted. If this routine is 
  1056    ** generating code because of a call to sqlite3NestedParse(), do not
  1057    ** invoke the callback function.
  1058    */
  1059    if( (db->flags&SQLITE_CountRows) && !pParse->nested && !pParse->pTriggerTab ){
  1060      sqlite3VdbeAddOp2(v, OP_ResultRow, regRowCount, 1);
  1061      sqlite3VdbeSetNumCols(v, 1);
  1062      sqlite3VdbeSetColName(v, 0, COLNAME_NAME, "rows inserted", SQLITE_STATIC);
  1063    }
  1064  
  1065  insert_cleanup:
  1066    sqlite3SrcListDelete(db, pTabList);
  1067    sqlite3ExprListDelete(db, pList);
  1068    sqlite3SelectDelete(db, pSelect);
  1069    sqlite3IdListDelete(db, pColumn);
  1070    sqlite3DbFree(db, aRegIdx);
  1071  }
  1072  
  1073  /* Make sure "isView" and other macros defined above are undefined. Otherwise
  1074  ** they may interfere with compilation of other functions in this file
  1075  ** (or in another file, if this file becomes part of the amalgamation).  */
  1076  #ifdef isView
  1077   #undef isView
  1078  #endif
  1079  #ifdef pTrigger
  1080   #undef pTrigger
  1081  #endif
  1082  #ifdef tmask
  1083   #undef tmask
  1084  #endif
  1085  
  1086  /*
  1087  ** Meanings of bits in of pWalker->eCode for checkConstraintUnchanged()
  1088  */
  1089  #define CKCNSTRNT_COLUMN   0x01    /* CHECK constraint uses a changing column */
  1090  #define CKCNSTRNT_ROWID    0x02    /* CHECK constraint references the ROWID */
  1091  
  1092  /* This is the Walker callback from checkConstraintUnchanged().  Set
  1093  ** bit 0x01 of pWalker->eCode if
  1094  ** pWalker->eCode to 0 if this expression node references any of the
  1095  ** columns that are being modifed by an UPDATE statement.
  1096  */
  1097  static int checkConstraintExprNode(Walker *pWalker, Expr *pExpr){
  1098    if( pExpr->op==TK_COLUMN ){
  1099      assert( pExpr->iColumn>=0 || pExpr->iColumn==-1 );
  1100      if( pExpr->iColumn>=0 ){
  1101        if( pWalker->u.aiCol[pExpr->iColumn]>=0 ){
  1102          pWalker->eCode |= CKCNSTRNT_COLUMN;
  1103        }
  1104      }else{
  1105        pWalker->eCode |= CKCNSTRNT_ROWID;
  1106      }
  1107    }
  1108    return WRC_Continue;
  1109  }
  1110  
  1111  /*
  1112  ** pExpr is a CHECK constraint on a row that is being UPDATE-ed.  The
  1113  ** only columns that are modified by the UPDATE are those for which
  1114  ** aiChng[i]>=0, and also the ROWID is modified if chngRowid is true.
  1115  **
  1116  ** Return true if CHECK constraint pExpr does not use any of the
  1117  ** changing columns (or the rowid if it is changing).  In other words,
  1118  ** return true if this CHECK constraint can be skipped when validating
  1119  ** the new row in the UPDATE statement.
  1120  */
  1121  static int checkConstraintUnchanged(Expr *pExpr, int *aiChng, int chngRowid){
  1122    Walker w;
  1123    memset(&w, 0, sizeof(w));
  1124    w.eCode = 0;
  1125    w.xExprCallback = checkConstraintExprNode;
  1126    w.u.aiCol = aiChng;
  1127    sqlite3WalkExpr(&w, pExpr);
  1128    if( !chngRowid ){
  1129      testcase( (w.eCode & CKCNSTRNT_ROWID)!=0 );
  1130      w.eCode &= ~CKCNSTRNT_ROWID;
  1131    }
  1132    testcase( w.eCode==0 );
  1133    testcase( w.eCode==CKCNSTRNT_COLUMN );
  1134    testcase( w.eCode==CKCNSTRNT_ROWID );
  1135    testcase( w.eCode==(CKCNSTRNT_ROWID|CKCNSTRNT_COLUMN) );
  1136    return !w.eCode;
  1137  }
  1138  
  1139  /*
  1140  ** Generate code to do constraint checks prior to an INSERT or an UPDATE
  1141  ** on table pTab.
  1142  **
  1143  ** The regNewData parameter is the first register in a range that contains
  1144  ** the data to be inserted or the data after the update.  There will be
  1145  ** pTab->nCol+1 registers in this range.  The first register (the one
  1146  ** that regNewData points to) will contain the new rowid, or NULL in the
  1147  ** case of a WITHOUT ROWID table.  The second register in the range will
  1148  ** contain the content of the first table column.  The third register will
  1149  ** contain the content of the second table column.  And so forth.
  1150  **
  1151  ** The regOldData parameter is similar to regNewData except that it contains
  1152  ** the data prior to an UPDATE rather than afterwards.  regOldData is zero
  1153  ** for an INSERT.  This routine can distinguish between UPDATE and INSERT by
  1154  ** checking regOldData for zero.
  1155  **
  1156  ** For an UPDATE, the pkChng boolean is true if the true primary key (the
  1157  ** rowid for a normal table or the PRIMARY KEY for a WITHOUT ROWID table)
  1158  ** might be modified by the UPDATE.  If pkChng is false, then the key of
  1159  ** the iDataCur content table is guaranteed to be unchanged by the UPDATE.
  1160  **
  1161  ** For an INSERT, the pkChng boolean indicates whether or not the rowid
  1162  ** was explicitly specified as part of the INSERT statement.  If pkChng
  1163  ** is zero, it means that the either rowid is computed automatically or
  1164  ** that the table is a WITHOUT ROWID table and has no rowid.  On an INSERT,
  1165  ** pkChng will only be true if the INSERT statement provides an integer
  1166  ** value for either the rowid column or its INTEGER PRIMARY KEY alias.
  1167  **
  1168  ** The code generated by this routine will store new index entries into
  1169  ** registers identified by aRegIdx[].  No index entry is created for
  1170  ** indices where aRegIdx[i]==0.  The order of indices in aRegIdx[] is
  1171  ** the same as the order of indices on the linked list of indices
  1172  ** at pTab->pIndex.
  1173  **
  1174  ** The caller must have already opened writeable cursors on the main
  1175  ** table and all applicable indices (that is to say, all indices for which
  1176  ** aRegIdx[] is not zero).  iDataCur is the cursor for the main table when
  1177  ** inserting or updating a rowid table, or the cursor for the PRIMARY KEY
  1178  ** index when operating on a WITHOUT ROWID table.  iIdxCur is the cursor
  1179  ** for the first index in the pTab->pIndex list.  Cursors for other indices
  1180  ** are at iIdxCur+N for the N-th element of the pTab->pIndex list.
  1181  **
  1182  ** This routine also generates code to check constraints.  NOT NULL,
  1183  ** CHECK, and UNIQUE constraints are all checked.  If a constraint fails,
  1184  ** then the appropriate action is performed.  There are five possible
  1185  ** actions: ROLLBACK, ABORT, FAIL, REPLACE, and IGNORE.
  1186  **
  1187  **  Constraint type  Action       What Happens
  1188  **  ---------------  ----------   ----------------------------------------
  1189  **  any              ROLLBACK     The current transaction is rolled back and
  1190  **                                sqlite3_step() returns immediately with a
  1191  **                                return code of SQLITE_CONSTRAINT.
  1192  **
  1193  **  any              ABORT        Back out changes from the current command
  1194  **                                only (do not do a complete rollback) then
  1195  **                                cause sqlite3_step() to return immediately
  1196  **                                with SQLITE_CONSTRAINT.
  1197  **
  1198  **  any              FAIL         Sqlite3_step() returns immediately with a
  1199  **                                return code of SQLITE_CONSTRAINT.  The
  1200  **                                transaction is not rolled back and any
  1201  **                                changes to prior rows are retained.
  1202  **
  1203  **  any              IGNORE       The attempt in insert or update the current
  1204  **                                row is skipped, without throwing an error.
  1205  **                                Processing continues with the next row.
  1206  **                                (There is an immediate jump to ignoreDest.)
  1207  **
  1208  **  NOT NULL         REPLACE      The NULL value is replace by the default
  1209  **                                value for that column.  If the default value
  1210  **                                is NULL, the action is the same as ABORT.
  1211  **
  1212  **  UNIQUE           REPLACE      The other row that conflicts with the row
  1213  **                                being inserted is removed.
  1214  **
  1215  **  CHECK            REPLACE      Illegal.  The results in an exception.
  1216  **
  1217  ** Which action to take is determined by the overrideError parameter.
  1218  ** Or if overrideError==OE_Default, then the pParse->onError parameter
  1219  ** is used.  Or if pParse->onError==OE_Default then the onError value
  1220  ** for the constraint is used.
  1221  */
  1222  void sqlite3GenerateConstraintChecks(
  1223    Parse *pParse,       /* The parser context */
  1224    Table *pTab,         /* The table being inserted or updated */
  1225    int *aRegIdx,        /* Use register aRegIdx[i] for index i.  0 for unused */
  1226    int iDataCur,        /* Canonical data cursor (main table or PK index) */
  1227    int iIdxCur,         /* First index cursor */
  1228    int regNewData,      /* First register in a range holding values to insert */
  1229    int regOldData,      /* Previous content.  0 for INSERTs */
  1230    u8 pkChng,           /* Non-zero if the rowid or PRIMARY KEY changed */
  1231    u8 overrideError,    /* Override onError to this if not OE_Default */
  1232    int ignoreDest,      /* Jump to this label on an OE_Ignore resolution */
  1233    int *pbMayReplace,   /* OUT: Set to true if constraint may cause a replace */
  1234    int *aiChng          /* column i is unchanged if aiChng[i]<0 */
  1235  ){
  1236    Vdbe *v;             /* VDBE under constrution */
  1237    Index *pIdx;         /* Pointer to one of the indices */
  1238    Index *pPk = 0;      /* The PRIMARY KEY index */
  1239    sqlite3 *db;         /* Database connection */
  1240    int i;               /* loop counter */
  1241    int ix;              /* Index loop counter */
  1242    int nCol;            /* Number of columns */
  1243    int onError;         /* Conflict resolution strategy */
  1244    int addr1;           /* Address of jump instruction */
  1245    int seenReplace = 0; /* True if REPLACE is used to resolve INT PK conflict */
  1246    int nPkField;        /* Number of fields in PRIMARY KEY. 1 for ROWID tables */
  1247    int ipkTop = 0;      /* Top of the rowid change constraint check */
  1248    int ipkBottom = 0;   /* Bottom of the rowid change constraint check */
  1249    u8 isUpdate;         /* True if this is an UPDATE operation */
  1250    u8 bAffinityDone = 0;  /* True if the OP_Affinity operation has been run */
  1251  
  1252    isUpdate = regOldData!=0;
  1253    db = pParse->db;
  1254    v = sqlite3GetVdbe(pParse);
  1255    assert( v!=0 );
  1256    assert( pTab->pSelect==0 );  /* This table is not a VIEW */
  1257    nCol = pTab->nCol;
  1258    
  1259    /* pPk is the PRIMARY KEY index for WITHOUT ROWID tables and NULL for
  1260    ** normal rowid tables.  nPkField is the number of key fields in the 
  1261    ** pPk index or 1 for a rowid table.  In other words, nPkField is the
  1262    ** number of fields in the true primary key of the table. */
  1263    if( HasRowid(pTab) ){
  1264      pPk = 0;
  1265      nPkField = 1;
  1266    }else{
  1267      pPk = sqlite3PrimaryKeyIndex(pTab);
  1268      nPkField = pPk->nKeyCol;
  1269    }
  1270  
  1271    /* Record that this module has started */
  1272    VdbeModuleComment((v, "BEGIN: GenCnstCks(%d,%d,%d,%d,%d)",
  1273                       iDataCur, iIdxCur, regNewData, regOldData, pkChng));
  1274  
  1275    /* Test all NOT NULL constraints.
  1276    */
  1277    for(i=0; i<nCol; i++){
  1278      if( i==pTab->iPKey ){
  1279        continue;        /* ROWID is never NULL */
  1280      }
  1281      if( aiChng && aiChng[i]<0 ){
  1282        /* Don't bother checking for NOT NULL on columns that do not change */
  1283        continue;
  1284      }
  1285      onError = pTab->aCol[i].notNull;
  1286      if( onError==OE_None ) continue;  /* This column is allowed to be NULL */
  1287      if( overrideError!=OE_Default ){
  1288        onError = overrideError;
  1289      }else if( onError==OE_Default ){
  1290        onError = OE_Abort;
  1291      }
  1292      if( onError==OE_Replace && pTab->aCol[i].pDflt==0 ){
  1293        onError = OE_Abort;
  1294      }
  1295      assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
  1296          || onError==OE_Ignore || onError==OE_Replace );
  1297      switch( onError ){
  1298        case OE_Abort:
  1299          sqlite3MayAbort(pParse);
  1300          /* Fall through */
  1301        case OE_Rollback:
  1302        case OE_Fail: {
  1303          char *zMsg = sqlite3MPrintf(db, "%s.%s", pTab->zName,
  1304                                      pTab->aCol[i].zName);
  1305          sqlite3VdbeAddOp3(v, OP_HaltIfNull, SQLITE_CONSTRAINT_NOTNULL, onError,
  1306                            regNewData+1+i);
  1307          sqlite3VdbeAppendP4(v, zMsg, P4_DYNAMIC);
  1308          sqlite3VdbeChangeP5(v, P5_ConstraintNotNull);
  1309          VdbeCoverage(v);
  1310          break;
  1311        }
  1312        case OE_Ignore: {
  1313          sqlite3VdbeAddOp2(v, OP_IsNull, regNewData+1+i, ignoreDest);
  1314          VdbeCoverage(v);
  1315          break;
  1316        }
  1317        default: {
  1318          assert( onError==OE_Replace );
  1319          addr1 = sqlite3VdbeAddOp1(v, OP_NotNull, regNewData+1+i);
  1320             VdbeCoverage(v);
  1321          sqlite3ExprCode(pParse, pTab->aCol[i].pDflt, regNewData+1+i);
  1322          sqlite3VdbeJumpHere(v, addr1);
  1323          break;
  1324        }
  1325      }
  1326    }
  1327  
  1328    /* Test all CHECK constraints
  1329    */
  1330  #ifndef SQLITE_OMIT_CHECK
  1331    if( pTab->pCheck && (db->flags & SQLITE_IgnoreChecks)==0 ){
  1332      ExprList *pCheck = pTab->pCheck;
  1333      pParse->iSelfTab = -(regNewData+1);
  1334      onError = overrideError!=OE_Default ? overrideError : OE_Abort;
  1335      for(i=0; i<pCheck->nExpr; i++){
  1336        int allOk;
  1337        Expr *pExpr = pCheck->a[i].pExpr;
  1338        if( aiChng && checkConstraintUnchanged(pExpr, aiChng, pkChng) ) continue;
  1339        allOk = sqlite3VdbeMakeLabel(v);
  1340        sqlite3ExprIfTrue(pParse, pExpr, allOk, SQLITE_JUMPIFNULL);
  1341        if( onError==OE_Ignore ){
  1342          sqlite3VdbeGoto(v, ignoreDest);
  1343        }else{
  1344          char *zName = pCheck->a[i].zName;
  1345          if( zName==0 ) zName = pTab->zName;
  1346          if( onError==OE_Replace ) onError = OE_Abort; /* IMP: R-15569-63625 */
  1347          sqlite3HaltConstraint(pParse, SQLITE_CONSTRAINT_CHECK,
  1348                                onError, zName, P4_TRANSIENT,
  1349                                P5_ConstraintCheck);
  1350        }
  1351        sqlite3VdbeResolveLabel(v, allOk);
  1352      }
  1353      pParse->iSelfTab = 0;
  1354    }
  1355  #endif /* !defined(SQLITE_OMIT_CHECK) */
  1356  
  1357    /* If rowid is changing, make sure the new rowid does not previously
  1358    ** exist in the table.
  1359    */
  1360    if( pkChng && pPk==0 ){
  1361      int addrRowidOk = sqlite3VdbeMakeLabel(v);
  1362  
  1363      /* Figure out what action to take in case of a rowid collision */
  1364      onError = pTab->keyConf;
  1365      if( overrideError!=OE_Default ){
  1366        onError = overrideError;
  1367      }else if( onError==OE_Default ){
  1368        onError = OE_Abort;
  1369      }
  1370  
  1371      if( isUpdate ){
  1372        /* pkChng!=0 does not mean that the rowid has changed, only that
  1373        ** it might have changed.  Skip the conflict logic below if the rowid
  1374        ** is unchanged. */
  1375        sqlite3VdbeAddOp3(v, OP_Eq, regNewData, addrRowidOk, regOldData);
  1376        sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
  1377        VdbeCoverage(v);
  1378      }
  1379  
  1380      /* If the response to a rowid conflict is REPLACE but the response
  1381      ** to some other UNIQUE constraint is FAIL or IGNORE, then we need
  1382      ** to defer the running of the rowid conflict checking until after
  1383      ** the UNIQUE constraints have run.
  1384      */
  1385      if( onError==OE_Replace && overrideError!=OE_Replace ){
  1386        for(pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext){
  1387          if( pIdx->onError==OE_Ignore || pIdx->onError==OE_Fail ){
  1388            ipkTop = sqlite3VdbeAddOp0(v, OP_Goto);
  1389            break;
  1390          }
  1391        }
  1392      }
  1393  
  1394      /* Check to see if the new rowid already exists in the table.  Skip
  1395      ** the following conflict logic if it does not. */
  1396      sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, addrRowidOk, regNewData);
  1397      VdbeCoverage(v);
  1398  
  1399      /* Generate code that deals with a rowid collision */
  1400      switch( onError ){
  1401        default: {
  1402          onError = OE_Abort;
  1403          /* Fall thru into the next case */
  1404        }
  1405        case OE_Rollback:
  1406        case OE_Abort:
  1407        case OE_Fail: {
  1408          sqlite3RowidConstraint(pParse, onError, pTab);
  1409          break;
  1410        }
  1411        case OE_Replace: {
  1412          /* If there are DELETE triggers on this table and the
  1413          ** recursive-triggers flag is set, call GenerateRowDelete() to
  1414          ** remove the conflicting row from the table. This will fire
  1415          ** the triggers and remove both the table and index b-tree entries.
  1416          **
  1417          ** Otherwise, if there are no triggers or the recursive-triggers
  1418          ** flag is not set, but the table has one or more indexes, call 
  1419          ** GenerateRowIndexDelete(). This removes the index b-tree entries 
  1420          ** only. The table b-tree entry will be replaced by the new entry 
  1421          ** when it is inserted.  
  1422          **
  1423          ** If either GenerateRowDelete() or GenerateRowIndexDelete() is called,
  1424          ** also invoke MultiWrite() to indicate that this VDBE may require
  1425          ** statement rollback (if the statement is aborted after the delete
  1426          ** takes place). Earlier versions called sqlite3MultiWrite() regardless,
  1427          ** but being more selective here allows statements like:
  1428          **
  1429          **   REPLACE INTO t(rowid) VALUES($newrowid)
  1430          **
  1431          ** to run without a statement journal if there are no indexes on the
  1432          ** table.
  1433          */
  1434          Trigger *pTrigger = 0;
  1435          if( db->flags&SQLITE_RecTriggers ){
  1436            pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
  1437          }
  1438          if( pTrigger || sqlite3FkRequired(pParse, pTab, 0, 0) ){
  1439            sqlite3MultiWrite(pParse);
  1440            sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
  1441                                     regNewData, 1, 0, OE_Replace, 1, -1);
  1442          }else{
  1443  #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
  1444            if( HasRowid(pTab) ){
  1445              /* This OP_Delete opcode fires the pre-update-hook only. It does
  1446              ** not modify the b-tree. It is more efficient to let the coming
  1447              ** OP_Insert replace the existing entry than it is to delete the
  1448              ** existing entry and then insert a new one. */
  1449              sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, OPFLAG_ISNOOP);
  1450              sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
  1451            }
  1452  #endif /* SQLITE_ENABLE_PREUPDATE_HOOK */
  1453            if( pTab->pIndex ){
  1454              sqlite3MultiWrite(pParse);
  1455              sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur,0,-1);
  1456            }
  1457          }
  1458          seenReplace = 1;
  1459          break;
  1460        }
  1461        case OE_Ignore: {
  1462          /*assert( seenReplace==0 );*/
  1463          sqlite3VdbeGoto(v, ignoreDest);
  1464          break;
  1465        }
  1466      }
  1467      sqlite3VdbeResolveLabel(v, addrRowidOk);
  1468      if( ipkTop ){
  1469        ipkBottom = sqlite3VdbeAddOp0(v, OP_Goto);
  1470        sqlite3VdbeJumpHere(v, ipkTop);
  1471      }
  1472    }
  1473  
  1474    /* Test all UNIQUE constraints by creating entries for each UNIQUE
  1475    ** index and making sure that duplicate entries do not already exist.
  1476    ** Compute the revised record entries for indices as we go.
  1477    **
  1478    ** This loop also handles the case of the PRIMARY KEY index for a
  1479    ** WITHOUT ROWID table.
  1480    */
  1481    for(ix=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, ix++){
  1482      int regIdx;          /* Range of registers hold conent for pIdx */
  1483      int regR;            /* Range of registers holding conflicting PK */
  1484      int iThisCur;        /* Cursor for this UNIQUE index */
  1485      int addrUniqueOk;    /* Jump here if the UNIQUE constraint is satisfied */
  1486  
  1487      if( aRegIdx[ix]==0 ) continue;  /* Skip indices that do not change */
  1488      if( bAffinityDone==0 ){
  1489        sqlite3TableAffinity(v, pTab, regNewData+1);
  1490        bAffinityDone = 1;
  1491      }
  1492      iThisCur = iIdxCur+ix;
  1493      addrUniqueOk = sqlite3VdbeMakeLabel(v);
  1494  
  1495      /* Skip partial indices for which the WHERE clause is not true */
  1496      if( pIdx->pPartIdxWhere ){
  1497        sqlite3VdbeAddOp2(v, OP_Null, 0, aRegIdx[ix]);
  1498        pParse->iSelfTab = -(regNewData+1);
  1499        sqlite3ExprIfFalseDup(pParse, pIdx->pPartIdxWhere, addrUniqueOk,
  1500                              SQLITE_JUMPIFNULL);
  1501        pParse->iSelfTab = 0;
  1502      }
  1503  
  1504      /* Create a record for this index entry as it should appear after
  1505      ** the insert or update.  Store that record in the aRegIdx[ix] register
  1506      */
  1507      regIdx = aRegIdx[ix]+1;
  1508      for(i=0; i<pIdx->nColumn; i++){
  1509        int iField = pIdx->aiColumn[i];
  1510        int x;
  1511        if( iField==XN_EXPR ){
  1512          pParse->iSelfTab = -(regNewData+1);
  1513          sqlite3ExprCodeCopy(pParse, pIdx->aColExpr->a[i].pExpr, regIdx+i);
  1514          pParse->iSelfTab = 0;
  1515          VdbeComment((v, "%s column %d", pIdx->zName, i));
  1516        }else{
  1517          if( iField==XN_ROWID || iField==pTab->iPKey ){
  1518            x = regNewData;
  1519          }else{
  1520            x = iField + regNewData + 1;
  1521          }
  1522          sqlite3VdbeAddOp2(v, iField<0 ? OP_IntCopy : OP_SCopy, x, regIdx+i);
  1523          VdbeComment((v, "%s", iField<0 ? "rowid" : pTab->aCol[iField].zName));
  1524        }
  1525      }
  1526      sqlite3VdbeAddOp3(v, OP_MakeRecord, regIdx, pIdx->nColumn, aRegIdx[ix]);
  1527      VdbeComment((v, "for %s", pIdx->zName));
  1528  #ifdef SQLITE_ENABLE_NULL_TRIM
  1529      if( pIdx->idxType==2 ) sqlite3SetMakeRecordP5(v, pIdx->pTable);
  1530  #endif
  1531  
  1532      /* In an UPDATE operation, if this index is the PRIMARY KEY index 
  1533      ** of a WITHOUT ROWID table and there has been no change the
  1534      ** primary key, then no collision is possible.  The collision detection
  1535      ** logic below can all be skipped. */
  1536      if( isUpdate && pPk==pIdx && pkChng==0 ){
  1537        sqlite3VdbeResolveLabel(v, addrUniqueOk);
  1538        continue;
  1539      }
  1540  
  1541      /* Find out what action to take in case there is a uniqueness conflict */
  1542      onError = pIdx->onError;
  1543      if( onError==OE_None ){ 
  1544        sqlite3VdbeResolveLabel(v, addrUniqueOk);
  1545        continue;  /* pIdx is not a UNIQUE index */
  1546      }
  1547      if( overrideError!=OE_Default ){
  1548        onError = overrideError;
  1549      }else if( onError==OE_Default ){
  1550        onError = OE_Abort;
  1551      }
  1552  
  1553      /* Collision detection may be omitted if all of the following are true:
  1554      **   (1) The conflict resolution algorithm is REPLACE
  1555      **   (2) The table is a WITHOUT ROWID table
  1556      **   (3) There are no secondary indexes on the table
  1557      **   (4) No delete triggers need to be fired if there is a conflict
  1558      **   (5) No FK constraint counters need to be updated if a conflict occurs.
  1559      */ 
  1560      if( (ix==0 && pIdx->pNext==0)                   /* Condition 3 */
  1561       && pPk==pIdx                                   /* Condition 2 */
  1562       && onError==OE_Replace                         /* Condition 1 */
  1563       && ( 0==(db->flags&SQLITE_RecTriggers) ||      /* Condition 4 */
  1564            0==sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0))
  1565       && ( 0==(db->flags&SQLITE_ForeignKeys) ||      /* Condition 5 */
  1566           (0==pTab->pFKey && 0==sqlite3FkReferences(pTab)))
  1567      ){
  1568        sqlite3VdbeResolveLabel(v, addrUniqueOk);
  1569        continue;
  1570      }
  1571  
  1572      /* Check to see if the new index entry will be unique */
  1573      sqlite3VdbeAddOp4Int(v, OP_NoConflict, iThisCur, addrUniqueOk,
  1574                           regIdx, pIdx->nKeyCol); VdbeCoverage(v);
  1575  
  1576      /* Generate code to handle collisions */
  1577      regR = (pIdx==pPk) ? regIdx : sqlite3GetTempRange(pParse, nPkField);
  1578      if( isUpdate || onError==OE_Replace ){
  1579        if( HasRowid(pTab) ){
  1580          sqlite3VdbeAddOp2(v, OP_IdxRowid, iThisCur, regR);
  1581          /* Conflict only if the rowid of the existing index entry
  1582          ** is different from old-rowid */
  1583          if( isUpdate ){
  1584            sqlite3VdbeAddOp3(v, OP_Eq, regR, addrUniqueOk, regOldData);
  1585            sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
  1586            VdbeCoverage(v);
  1587          }
  1588        }else{
  1589          int x;
  1590          /* Extract the PRIMARY KEY from the end of the index entry and
  1591          ** store it in registers regR..regR+nPk-1 */
  1592          if( pIdx!=pPk ){
  1593            for(i=0; i<pPk->nKeyCol; i++){
  1594              assert( pPk->aiColumn[i]>=0 );
  1595              x = sqlite3ColumnOfIndex(pIdx, pPk->aiColumn[i]);
  1596              sqlite3VdbeAddOp3(v, OP_Column, iThisCur, x, regR+i);
  1597              VdbeComment((v, "%s.%s", pTab->zName,
  1598                           pTab->aCol[pPk->aiColumn[i]].zName));
  1599            }
  1600          }
  1601          if( isUpdate ){
  1602            /* If currently processing the PRIMARY KEY of a WITHOUT ROWID 
  1603            ** table, only conflict if the new PRIMARY KEY values are actually
  1604            ** different from the old.
  1605            **
  1606            ** For a UNIQUE index, only conflict if the PRIMARY KEY values
  1607            ** of the matched index row are different from the original PRIMARY
  1608            ** KEY values of this row before the update.  */
  1609            int addrJump = sqlite3VdbeCurrentAddr(v)+pPk->nKeyCol;
  1610            int op = OP_Ne;
  1611            int regCmp = (IsPrimaryKeyIndex(pIdx) ? regIdx : regR);
  1612    
  1613            for(i=0; i<pPk->nKeyCol; i++){
  1614              char *p4 = (char*)sqlite3LocateCollSeq(pParse, pPk->azColl[i]);
  1615              x = pPk->aiColumn[i];
  1616              assert( x>=0 );
  1617              if( i==(pPk->nKeyCol-1) ){
  1618                addrJump = addrUniqueOk;
  1619                op = OP_Eq;
  1620              }
  1621              sqlite3VdbeAddOp4(v, op, 
  1622                  regOldData+1+x, addrJump, regCmp+i, p4, P4_COLLSEQ
  1623              );
  1624              sqlite3VdbeChangeP5(v, SQLITE_NOTNULL);
  1625              VdbeCoverageIf(v, op==OP_Eq);
  1626              VdbeCoverageIf(v, op==OP_Ne);
  1627            }
  1628          }
  1629        }
  1630      }
  1631  
  1632      /* Generate code that executes if the new index entry is not unique */
  1633      assert( onError==OE_Rollback || onError==OE_Abort || onError==OE_Fail
  1634          || onError==OE_Ignore || onError==OE_Replace );
  1635      switch( onError ){
  1636        case OE_Rollback:
  1637        case OE_Abort:
  1638        case OE_Fail: {
  1639          sqlite3UniqueConstraint(pParse, onError, pIdx);
  1640          break;
  1641        }
  1642        case OE_Ignore: {
  1643          sqlite3VdbeGoto(v, ignoreDest);
  1644          break;
  1645        }
  1646        default: {
  1647          Trigger *pTrigger = 0;
  1648          assert( onError==OE_Replace );
  1649          sqlite3MultiWrite(pParse);
  1650          if( db->flags&SQLITE_RecTriggers ){
  1651            pTrigger = sqlite3TriggersExist(pParse, pTab, TK_DELETE, 0, 0);
  1652          }
  1653          sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
  1654              regR, nPkField, 0, OE_Replace,
  1655              (pIdx==pPk ? ONEPASS_SINGLE : ONEPASS_OFF), iThisCur);
  1656          seenReplace = 1;
  1657          break;
  1658        }
  1659      }
  1660      sqlite3VdbeResolveLabel(v, addrUniqueOk);
  1661      if( regR!=regIdx ) sqlite3ReleaseTempRange(pParse, regR, nPkField);
  1662    }
  1663    if( ipkTop ){
  1664      sqlite3VdbeGoto(v, ipkTop+1);
  1665      sqlite3VdbeJumpHere(v, ipkBottom);
  1666    }
  1667    
  1668    *pbMayReplace = seenReplace;
  1669    VdbeModuleComment((v, "END: GenCnstCks(%d)", seenReplace));
  1670  }
  1671  
  1672  #ifdef SQLITE_ENABLE_NULL_TRIM
  1673  /*
  1674  ** Change the P5 operand on the last opcode (which should be an OP_MakeRecord)
  1675  ** to be the number of columns in table pTab that must not be NULL-trimmed.
  1676  **
  1677  ** Or if no columns of pTab may be NULL-trimmed, leave P5 at zero.
  1678  */
  1679  void sqlite3SetMakeRecordP5(Vdbe *v, Table *pTab){
  1680    u16 i;
  1681  
  1682    /* Records with omitted columns are only allowed for schema format
  1683    ** version 2 and later (SQLite version 3.1.4, 2005-02-20). */
  1684    if( pTab->pSchema->file_format<2 ) return;
  1685  
  1686    for(i=pTab->nCol-1; i>0; i--){
  1687      if( pTab->aCol[i].pDflt!=0 ) break;
  1688      if( pTab->aCol[i].colFlags & COLFLAG_PRIMKEY ) break;
  1689    }
  1690    sqlite3VdbeChangeP5(v, i+1);
  1691  }
  1692  #endif
  1693  
  1694  /*
  1695  ** This routine generates code to finish the INSERT or UPDATE operation
  1696  ** that was started by a prior call to sqlite3GenerateConstraintChecks.
  1697  ** A consecutive range of registers starting at regNewData contains the
  1698  ** rowid and the content to be inserted.
  1699  **
  1700  ** The arguments to this routine should be the same as the first six
  1701  ** arguments to sqlite3GenerateConstraintChecks.
  1702  */
  1703  void sqlite3CompleteInsertion(
  1704    Parse *pParse,      /* The parser context */
  1705    Table *pTab,        /* the table into which we are inserting */
  1706    int iDataCur,       /* Cursor of the canonical data source */
  1707    int iIdxCur,        /* First index cursor */
  1708    int regNewData,     /* Range of content */
  1709    int *aRegIdx,       /* Register used by each index.  0 for unused indices */
  1710    int update_flags,   /* True for UPDATE, False for INSERT */
  1711    int appendBias,     /* True if this is likely to be an append */
  1712    int useSeekResult   /* True to set the USESEEKRESULT flag on OP_[Idx]Insert */
  1713  ){
  1714    Vdbe *v;            /* Prepared statements under construction */
  1715    Index *pIdx;        /* An index being inserted or updated */
  1716    u8 pik_flags;       /* flag values passed to the btree insert */
  1717    int regData;        /* Content registers (after the rowid) */
  1718    int regRec;         /* Register holding assembled record for the table */
  1719    int i;              /* Loop counter */
  1720    u8 bAffinityDone = 0; /* True if OP_Affinity has been run already */
  1721  
  1722    assert( update_flags==0
  1723         || update_flags==OPFLAG_ISUPDATE
  1724         || update_flags==(OPFLAG_ISUPDATE|OPFLAG_SAVEPOSITION)
  1725    );
  1726  
  1727    v = sqlite3GetVdbe(pParse);
  1728    assert( v!=0 );
  1729    assert( pTab->pSelect==0 );  /* This table is not a VIEW */
  1730    for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
  1731      if( aRegIdx[i]==0 ) continue;
  1732      bAffinityDone = 1;
  1733      if( pIdx->pPartIdxWhere ){
  1734        sqlite3VdbeAddOp2(v, OP_IsNull, aRegIdx[i], sqlite3VdbeCurrentAddr(v)+2);
  1735        VdbeCoverage(v);
  1736      }
  1737      pik_flags = (useSeekResult ? OPFLAG_USESEEKRESULT : 0);
  1738      if( IsPrimaryKeyIndex(pIdx) && !HasRowid(pTab) ){
  1739        assert( pParse->nested==0 );
  1740        pik_flags |= OPFLAG_NCHANGE;
  1741        pik_flags |= (update_flags & OPFLAG_SAVEPOSITION);
  1742  #ifdef SQLITE_ENABLE_PREUPDATE_HOOK
  1743        if( update_flags==0 ){
  1744          sqlite3VdbeAddOp4(v, OP_InsertInt, 
  1745              iIdxCur+i, aRegIdx[i], 0, (char*)pTab, P4_TABLE
  1746          );
  1747          sqlite3VdbeChangeP5(v, OPFLAG_ISNOOP);
  1748        }
  1749  #endif
  1750      }
  1751      sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iIdxCur+i, aRegIdx[i],
  1752                           aRegIdx[i]+1,
  1753                           pIdx->uniqNotNull ? pIdx->nKeyCol: pIdx->nColumn);
  1754      sqlite3VdbeChangeP5(v, pik_flags);
  1755    }
  1756    if( !HasRowid(pTab) ) return;
  1757    regData = regNewData + 1;
  1758    regRec = sqlite3GetTempReg(pParse);
  1759    sqlite3VdbeAddOp3(v, OP_MakeRecord, regData, pTab->nCol, regRec);
  1760    sqlite3SetMakeRecordP5(v, pTab);
  1761    if( !bAffinityDone ){
  1762      sqlite3TableAffinity(v, pTab, 0);
  1763      sqlite3ExprCacheAffinityChange(pParse, regData, pTab->nCol);
  1764    }
  1765    if( pParse->nested ){
  1766      pik_flags = 0;
  1767    }else{
  1768      pik_flags = OPFLAG_NCHANGE;
  1769      pik_flags |= (update_flags?update_flags:OPFLAG_LASTROWID);
  1770    }
  1771    if( appendBias ){
  1772      pik_flags |= OPFLAG_APPEND;
  1773    }
  1774    if( useSeekResult ){
  1775      pik_flags |= OPFLAG_USESEEKRESULT;
  1776    }
  1777    sqlite3VdbeAddOp3(v, OP_Insert, iDataCur, regRec, regNewData);
  1778    if( !pParse->nested ){
  1779      sqlite3VdbeAppendP4(v, pTab, P4_TABLE);
  1780    }
  1781    sqlite3VdbeChangeP5(v, pik_flags);
  1782  }
  1783  
  1784  /*
  1785  ** Allocate cursors for the pTab table and all its indices and generate
  1786  ** code to open and initialized those cursors.
  1787  **
  1788  ** The cursor for the object that contains the complete data (normally
  1789  ** the table itself, but the PRIMARY KEY index in the case of a WITHOUT
  1790  ** ROWID table) is returned in *piDataCur.  The first index cursor is
  1791  ** returned in *piIdxCur.  The number of indices is returned.
  1792  **
  1793  ** Use iBase as the first cursor (either the *piDataCur for rowid tables
  1794  ** or the first index for WITHOUT ROWID tables) if it is non-negative.
  1795  ** If iBase is negative, then allocate the next available cursor.
  1796  **
  1797  ** For a rowid table, *piDataCur will be exactly one less than *piIdxCur.
  1798  ** For a WITHOUT ROWID table, *piDataCur will be somewhere in the range
  1799  ** of *piIdxCurs, depending on where the PRIMARY KEY index appears on the
  1800  ** pTab->pIndex list.
  1801  **
  1802  ** If pTab is a virtual table, then this routine is a no-op and the
  1803  ** *piDataCur and *piIdxCur values are left uninitialized.
  1804  */
  1805  int sqlite3OpenTableAndIndices(
  1806    Parse *pParse,   /* Parsing context */
  1807    Table *pTab,     /* Table to be opened */
  1808    int op,          /* OP_OpenRead or OP_OpenWrite */
  1809    u8 p5,           /* P5 value for OP_Open* opcodes (except on WITHOUT ROWID) */
  1810    int iBase,       /* Use this for the table cursor, if there is one */
  1811    u8 *aToOpen,     /* If not NULL: boolean for each table and index */
  1812    int *piDataCur,  /* Write the database source cursor number here */
  1813    int *piIdxCur    /* Write the first index cursor number here */
  1814  ){
  1815    int i;
  1816    int iDb;
  1817    int iDataCur;
  1818    Index *pIdx;
  1819    Vdbe *v;
  1820  
  1821    assert( op==OP_OpenRead || op==OP_OpenWrite );
  1822    assert( op==OP_OpenWrite || p5==0 );
  1823    if( IsVirtual(pTab) ){
  1824      /* This routine is a no-op for virtual tables. Leave the output
  1825      ** variables *piDataCur and *piIdxCur uninitialized so that valgrind
  1826      ** can detect if they are used by mistake in the caller. */
  1827      return 0;
  1828    }
  1829    iDb = sqlite3SchemaToIndex(pParse->db, pTab->pSchema);
  1830    v = sqlite3GetVdbe(pParse);
  1831    assert( v!=0 );
  1832    if( iBase<0 ) iBase = pParse->nTab;
  1833    iDataCur = iBase++;
  1834    if( piDataCur ) *piDataCur = iDataCur;
  1835    if( HasRowid(pTab) && (aToOpen==0 || aToOpen[0]) ){
  1836      sqlite3OpenTable(pParse, iDataCur, iDb, pTab, op);
  1837    }else{
  1838      sqlite3TableLock(pParse, iDb, pTab->tnum, op==OP_OpenWrite, pTab->zName);
  1839    }
  1840    if( piIdxCur ) *piIdxCur = iBase;
  1841    for(i=0, pIdx=pTab->pIndex; pIdx; pIdx=pIdx->pNext, i++){
  1842      int iIdxCur = iBase++;
  1843      assert( pIdx->pSchema==pTab->pSchema );
  1844      if( IsPrimaryKeyIndex(pIdx) && !HasRowid(pTab) ){
  1845        if( piDataCur ) *piDataCur = iIdxCur;
  1846        p5 = 0;
  1847      }
  1848      if( aToOpen==0 || aToOpen[i+1] ){
  1849        sqlite3VdbeAddOp3(v, op, iIdxCur, pIdx->tnum, iDb);
  1850        sqlite3VdbeSetP4KeyInfo(pParse, pIdx);
  1851        sqlite3VdbeChangeP5(v, p5);
  1852        VdbeComment((v, "%s", pIdx->zName));
  1853      }
  1854    }
  1855    if( iBase>pParse->nTab ) pParse->nTab = iBase;
  1856    return i;
  1857  }
  1858  
  1859  
  1860  #ifdef SQLITE_TEST
  1861  /*
  1862  ** The following global variable is incremented whenever the
  1863  ** transfer optimization is used.  This is used for testing
  1864  ** purposes only - to make sure the transfer optimization really
  1865  ** is happening when it is supposed to.
  1866  */
  1867  int sqlite3_xferopt_count;
  1868  #endif /* SQLITE_TEST */
  1869  
  1870  
  1871  #ifndef SQLITE_OMIT_XFER_OPT
  1872  /*
  1873  ** Check to see if index pSrc is compatible as a source of data
  1874  ** for index pDest in an insert transfer optimization.  The rules
  1875  ** for a compatible index:
  1876  **
  1877  **    *   The index is over the same set of columns
  1878  **    *   The same DESC and ASC markings occurs on all columns
  1879  **    *   The same onError processing (OE_Abort, OE_Ignore, etc)
  1880  **    *   The same collating sequence on each column
  1881  **    *   The index has the exact same WHERE clause
  1882  */
  1883  static int xferCompatibleIndex(Index *pDest, Index *pSrc){
  1884    int i;
  1885    assert( pDest && pSrc );
  1886    assert( pDest->pTable!=pSrc->pTable );
  1887    if( pDest->nKeyCol!=pSrc->nKeyCol ){
  1888      return 0;   /* Different number of columns */
  1889    }
  1890    if( pDest->onError!=pSrc->onError ){
  1891      return 0;   /* Different conflict resolution strategies */
  1892    }
  1893    for(i=0; i<pSrc->nKeyCol; i++){
  1894      if( pSrc->aiColumn[i]!=pDest->aiColumn[i] ){
  1895        return 0;   /* Different columns indexed */
  1896      }
  1897      if( pSrc->aiColumn[i]==XN_EXPR ){
  1898        assert( pSrc->aColExpr!=0 && pDest->aColExpr!=0 );
  1899        if( sqlite3ExprCompare(0, pSrc->aColExpr->a[i].pExpr,
  1900                               pDest->aColExpr->a[i].pExpr, -1)!=0 ){
  1901          return 0;   /* Different expressions in the index */
  1902        }
  1903      }
  1904      if( pSrc->aSortOrder[i]!=pDest->aSortOrder[i] ){
  1905        return 0;   /* Different sort orders */
  1906      }
  1907      if( sqlite3_stricmp(pSrc->azColl[i],pDest->azColl[i])!=0 ){
  1908        return 0;   /* Different collating sequences */
  1909      }
  1910    }
  1911    if( sqlite3ExprCompare(0, pSrc->pPartIdxWhere, pDest->pPartIdxWhere, -1) ){
  1912      return 0;     /* Different WHERE clauses */
  1913    }
  1914  
  1915    /* If no test above fails then the indices must be compatible */
  1916    return 1;
  1917  }
  1918  
  1919  /*
  1920  ** Attempt the transfer optimization on INSERTs of the form
  1921  **
  1922  **     INSERT INTO tab1 SELECT * FROM tab2;
  1923  **
  1924  ** The xfer optimization transfers raw records from tab2 over to tab1.  
  1925  ** Columns are not decoded and reassembled, which greatly improves
  1926  ** performance.  Raw index records are transferred in the same way.
  1927  **
  1928  ** The xfer optimization is only attempted if tab1 and tab2 are compatible.
  1929  ** There are lots of rules for determining compatibility - see comments
  1930  ** embedded in the code for details.
  1931  **
  1932  ** This routine returns TRUE if the optimization is guaranteed to be used.
  1933  ** Sometimes the xfer optimization will only work if the destination table
  1934  ** is empty - a factor that can only be determined at run-time.  In that
  1935  ** case, this routine generates code for the xfer optimization but also
  1936  ** does a test to see if the destination table is empty and jumps over the
  1937  ** xfer optimization code if the test fails.  In that case, this routine
  1938  ** returns FALSE so that the caller will know to go ahead and generate
  1939  ** an unoptimized transfer.  This routine also returns FALSE if there
  1940  ** is no chance that the xfer optimization can be applied.
  1941  **
  1942  ** This optimization is particularly useful at making VACUUM run faster.
  1943  */
  1944  static int xferOptimization(
  1945    Parse *pParse,        /* Parser context */
  1946    Table *pDest,         /* The table we are inserting into */
  1947    Select *pSelect,      /* A SELECT statement to use as the data source */
  1948    int onError,          /* How to handle constraint errors */
  1949    int iDbDest           /* The database of pDest */
  1950  ){
  1951    sqlite3 *db = pParse->db;
  1952    ExprList *pEList;                /* The result set of the SELECT */
  1953    Table *pSrc;                     /* The table in the FROM clause of SELECT */
  1954    Index *pSrcIdx, *pDestIdx;       /* Source and destination indices */
  1955    struct SrcList_item *pItem;      /* An element of pSelect->pSrc */
  1956    int i;                           /* Loop counter */
  1957    int iDbSrc;                      /* The database of pSrc */
  1958    int iSrc, iDest;                 /* Cursors from source and destination */
  1959    int addr1, addr2;                /* Loop addresses */
  1960    int emptyDestTest = 0;           /* Address of test for empty pDest */
  1961    int emptySrcTest = 0;            /* Address of test for empty pSrc */
  1962    Vdbe *v;                         /* The VDBE we are building */
  1963    int regAutoinc;                  /* Memory register used by AUTOINC */
  1964    int destHasUniqueIdx = 0;        /* True if pDest has a UNIQUE index */
  1965    int regData, regRowid;           /* Registers holding data and rowid */
  1966  
  1967    if( pSelect==0 ){
  1968      return 0;   /* Must be of the form  INSERT INTO ... SELECT ... */
  1969    }
  1970    if( pParse->pWith || pSelect->pWith ){
  1971      /* Do not attempt to process this query if there are an WITH clauses
  1972      ** attached to it. Proceeding may generate a false "no such table: xxx"
  1973      ** error if pSelect reads from a CTE named "xxx".  */
  1974      return 0;
  1975    }
  1976    if( sqlite3TriggerList(pParse, pDest) ){
  1977      return 0;   /* tab1 must not have triggers */
  1978    }
  1979  #ifndef SQLITE_OMIT_VIRTUALTABLE
  1980    if( IsVirtual(pDest) ){
  1981      return 0;   /* tab1 must not be a virtual table */
  1982    }
  1983  #endif
  1984    if( onError==OE_Default ){
  1985      if( pDest->iPKey>=0 ) onError = pDest->keyConf;
  1986      if( onError==OE_Default ) onError = OE_Abort;
  1987    }
  1988    assert(pSelect->pSrc);   /* allocated even if there is no FROM clause */
  1989    if( pSelect->pSrc->nSrc!=1 ){
  1990      return 0;   /* FROM clause must have exactly one term */
  1991    }
  1992    if( pSelect->pSrc->a[0].pSelect ){
  1993      return 0;   /* FROM clause cannot contain a subquery */
  1994    }
  1995    if( pSelect->pWhere ){
  1996      return 0;   /* SELECT may not have a WHERE clause */
  1997    }
  1998    if( pSelect->pOrderBy ){
  1999      return 0;   /* SELECT may not have an ORDER BY clause */
  2000    }
  2001    /* Do not need to test for a HAVING clause.  If HAVING is present but
  2002    ** there is no ORDER BY, we will get an error. */
  2003    if( pSelect->pGroupBy ){
  2004      return 0;   /* SELECT may not have a GROUP BY clause */
  2005    }
  2006    if( pSelect->pLimit ){
  2007      return 0;   /* SELECT may not have a LIMIT clause */
  2008    }
  2009    assert( pSelect->pOffset==0 );  /* Must be so if pLimit==0 */
  2010    if( pSelect->pPrior ){
  2011      return 0;   /* SELECT may not be a compound query */
  2012    }
  2013    if( pSelect->selFlags & SF_Distinct ){
  2014      return 0;   /* SELECT may not be DISTINCT */
  2015    }
  2016    pEList = pSelect->pEList;
  2017    assert( pEList!=0 );
  2018    if( pEList->nExpr!=1 ){
  2019      return 0;   /* The result set must have exactly one column */
  2020    }
  2021    assert( pEList->a[0].pExpr );
  2022    if( pEList->a[0].pExpr->op!=TK_ASTERISK ){
  2023      return 0;   /* The result set must be the special operator "*" */
  2024    }
  2025  
  2026    /* At this point we have established that the statement is of the
  2027    ** correct syntactic form to participate in this optimization.  Now
  2028    ** we have to check the semantics.
  2029    */
  2030    pItem = pSelect->pSrc->a;
  2031    pSrc = sqlite3LocateTableItem(pParse, 0, pItem);
  2032    if( pSrc==0 ){
  2033      return 0;   /* FROM clause does not contain a real table */
  2034    }
  2035    if( pSrc==pDest ){
  2036      return 0;   /* tab1 and tab2 may not be the same table */
  2037    }
  2038    if( HasRowid(pDest)!=HasRowid(pSrc) ){
  2039      return 0;   /* source and destination must both be WITHOUT ROWID or not */
  2040    }
  2041  #ifndef SQLITE_OMIT_VIRTUALTABLE
  2042    if( IsVirtual(pSrc) ){
  2043      return 0;   /* tab2 must not be a virtual table */
  2044    }
  2045  #endif
  2046    if( pSrc->pSelect ){
  2047      return 0;   /* tab2 may not be a view */
  2048    }
  2049    if( pDest->nCol!=pSrc->nCol ){
  2050      return 0;   /* Number of columns must be the same in tab1 and tab2 */
  2051    }
  2052    if( pDest->iPKey!=pSrc->iPKey ){
  2053      return 0;   /* Both tables must have the same INTEGER PRIMARY KEY */
  2054    }
  2055    for(i=0; i<pDest->nCol; i++){
  2056      Column *pDestCol = &pDest->aCol[i];
  2057      Column *pSrcCol = &pSrc->aCol[i];
  2058  #ifdef SQLITE_ENABLE_HIDDEN_COLUMNS
  2059      if( (db->mDbFlags & DBFLAG_Vacuum)==0 
  2060       && (pDestCol->colFlags | pSrcCol->colFlags) & COLFLAG_HIDDEN 
  2061      ){
  2062        return 0;    /* Neither table may have __hidden__ columns */
  2063      }
  2064  #endif
  2065      if( pDestCol->affinity!=pSrcCol->affinity ){
  2066        return 0;    /* Affinity must be the same on all columns */
  2067      }
  2068      if( sqlite3_stricmp(pDestCol->zColl, pSrcCol->zColl)!=0 ){
  2069        return 0;    /* Collating sequence must be the same on all columns */
  2070      }
  2071      if( pDestCol->notNull && !pSrcCol->notNull ){
  2072        return 0;    /* tab2 must be NOT NULL if tab1 is */
  2073      }
  2074      /* Default values for second and subsequent columns need to match. */
  2075      if( i>0 ){
  2076        assert( pDestCol->pDflt==0 || pDestCol->pDflt->op==TK_SPAN );
  2077        assert( pSrcCol->pDflt==0 || pSrcCol->pDflt->op==TK_SPAN );
  2078        if( (pDestCol->pDflt==0)!=(pSrcCol->pDflt==0) 
  2079         || (pDestCol->pDflt && strcmp(pDestCol->pDflt->u.zToken,
  2080                                         pSrcCol->pDflt->u.zToken)!=0)
  2081        ){
  2082          return 0;    /* Default values must be the same for all columns */
  2083        }
  2084      }
  2085    }
  2086    for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
  2087      if( IsUniqueIndex(pDestIdx) ){
  2088        destHasUniqueIdx = 1;
  2089      }
  2090      for(pSrcIdx=pSrc->pIndex; pSrcIdx; pSrcIdx=pSrcIdx->pNext){
  2091        if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
  2092      }
  2093      if( pSrcIdx==0 ){
  2094        return 0;    /* pDestIdx has no corresponding index in pSrc */
  2095      }
  2096    }
  2097  #ifndef SQLITE_OMIT_CHECK
  2098    if( pDest->pCheck && sqlite3ExprListCompare(pSrc->pCheck,pDest->pCheck,-1) ){
  2099      return 0;   /* Tables have different CHECK constraints.  Ticket #2252 */
  2100    }
  2101  #endif
  2102  #ifndef SQLITE_OMIT_FOREIGN_KEY
  2103    /* Disallow the transfer optimization if the destination table constains
  2104    ** any foreign key constraints.  This is more restrictive than necessary.
  2105    ** But the main beneficiary of the transfer optimization is the VACUUM 
  2106    ** command, and the VACUUM command disables foreign key constraints.  So
  2107    ** the extra complication to make this rule less restrictive is probably
  2108    ** not worth the effort.  Ticket [6284df89debdfa61db8073e062908af0c9b6118e]
  2109    */
  2110    if( (db->flags & SQLITE_ForeignKeys)!=0 && pDest->pFKey!=0 ){
  2111      return 0;
  2112    }
  2113  #endif
  2114    if( (db->flags & SQLITE_CountRows)!=0 ){
  2115      return 0;  /* xfer opt does not play well with PRAGMA count_changes */
  2116    }
  2117  
  2118    /* If we get this far, it means that the xfer optimization is at
  2119    ** least a possibility, though it might only work if the destination
  2120    ** table (tab1) is initially empty.
  2121    */
  2122  #ifdef SQLITE_TEST
  2123    sqlite3_xferopt_count++;
  2124  #endif
  2125    iDbSrc = sqlite3SchemaToIndex(db, pSrc->pSchema);
  2126    v = sqlite3GetVdbe(pParse);
  2127    sqlite3CodeVerifySchema(pParse, iDbSrc);
  2128    iSrc = pParse->nTab++;
  2129    iDest = pParse->nTab++;
  2130    regAutoinc = autoIncBegin(pParse, iDbDest, pDest);
  2131    regData = sqlite3GetTempReg(pParse);
  2132    regRowid = sqlite3GetTempReg(pParse);
  2133    sqlite3OpenTable(pParse, iDest, iDbDest, pDest, OP_OpenWrite);
  2134    assert( HasRowid(pDest) || destHasUniqueIdx );
  2135    if( (db->mDbFlags & DBFLAG_Vacuum)==0 && (
  2136        (pDest->iPKey<0 && pDest->pIndex!=0)          /* (1) */
  2137     || destHasUniqueIdx                              /* (2) */
  2138     || (onError!=OE_Abort && onError!=OE_Rollback)   /* (3) */
  2139    )){
  2140      /* In some circumstances, we are able to run the xfer optimization
  2141      ** only if the destination table is initially empty. Unless the
  2142      ** DBFLAG_Vacuum flag is set, this block generates code to make
  2143      ** that determination. If DBFLAG_Vacuum is set, then the destination
  2144      ** table is always empty.
  2145      **
  2146      ** Conditions under which the destination must be empty:
  2147      **
  2148      ** (1) There is no INTEGER PRIMARY KEY but there are indices.
  2149      **     (If the destination is not initially empty, the rowid fields
  2150      **     of index entries might need to change.)
  2151      **
  2152      ** (2) The destination has a unique index.  (The xfer optimization 
  2153      **     is unable to test uniqueness.)
  2154      **
  2155      ** (3) onError is something other than OE_Abort and OE_Rollback.
  2156      */
  2157      addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iDest, 0); VdbeCoverage(v);
  2158      emptyDestTest = sqlite3VdbeAddOp0(v, OP_Goto);
  2159      sqlite3VdbeJumpHere(v, addr1);
  2160    }
  2161    if( HasRowid(pSrc) ){
  2162      u8 insFlags;
  2163      sqlite3OpenTable(pParse, iSrc, iDbSrc, pSrc, OP_OpenRead);
  2164      emptySrcTest = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0); VdbeCoverage(v);
  2165      if( pDest->iPKey>=0 ){
  2166        addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
  2167        addr2 = sqlite3VdbeAddOp3(v, OP_NotExists, iDest, 0, regRowid);
  2168        VdbeCoverage(v);
  2169        sqlite3RowidConstraint(pParse, onError, pDest);
  2170        sqlite3VdbeJumpHere(v, addr2);
  2171        autoIncStep(pParse, regAutoinc, regRowid);
  2172      }else if( pDest->pIndex==0 ){
  2173        addr1 = sqlite3VdbeAddOp2(v, OP_NewRowid, iDest, regRowid);
  2174      }else{
  2175        addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
  2176        assert( (pDest->tabFlags & TF_Autoincrement)==0 );
  2177      }
  2178      sqlite3VdbeAddOp3(v, OP_RowData, iSrc, regData, 1);
  2179      if( db->mDbFlags & DBFLAG_Vacuum ){
  2180        sqlite3VdbeAddOp1(v, OP_SeekEnd, iDest);
  2181        insFlags = OPFLAG_NCHANGE|OPFLAG_LASTROWID|
  2182                             OPFLAG_APPEND|OPFLAG_USESEEKRESULT;
  2183      }else{
  2184        insFlags = OPFLAG_NCHANGE|OPFLAG_LASTROWID|OPFLAG_APPEND;
  2185      }
  2186      sqlite3VdbeAddOp4(v, OP_Insert, iDest, regData, regRowid,
  2187                        (char*)pDest, P4_TABLE);
  2188      sqlite3VdbeChangeP5(v, insFlags);
  2189      sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1); VdbeCoverage(v);
  2190      sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
  2191      sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
  2192    }else{
  2193      sqlite3TableLock(pParse, iDbDest, pDest->tnum, 1, pDest->zName);
  2194      sqlite3TableLock(pParse, iDbSrc, pSrc->tnum, 0, pSrc->zName);
  2195    }
  2196    for(pDestIdx=pDest->pIndex; pDestIdx; pDestIdx=pDestIdx->pNext){
  2197      u8 idxInsFlags = 0;
  2198      for(pSrcIdx=pSrc->pIndex; ALWAYS(pSrcIdx); pSrcIdx=pSrcIdx->pNext){
  2199        if( xferCompatibleIndex(pDestIdx, pSrcIdx) ) break;
  2200      }
  2201      assert( pSrcIdx );
  2202      sqlite3VdbeAddOp3(v, OP_OpenRead, iSrc, pSrcIdx->tnum, iDbSrc);
  2203      sqlite3VdbeSetP4KeyInfo(pParse, pSrcIdx);
  2204      VdbeComment((v, "%s", pSrcIdx->zName));
  2205      sqlite3VdbeAddOp3(v, OP_OpenWrite, iDest, pDestIdx->tnum, iDbDest);
  2206      sqlite3VdbeSetP4KeyInfo(pParse, pDestIdx);
  2207      sqlite3VdbeChangeP5(v, OPFLAG_BULKCSR);
  2208      VdbeComment((v, "%s", pDestIdx->zName));
  2209      addr1 = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0); VdbeCoverage(v);
  2210      sqlite3VdbeAddOp3(v, OP_RowData, iSrc, regData, 1);
  2211      if( db->mDbFlags & DBFLAG_Vacuum ){
  2212        /* This INSERT command is part of a VACUUM operation, which guarantees
  2213        ** that the destination table is empty. If all indexed columns use
  2214        ** collation sequence BINARY, then it can also be assumed that the
  2215        ** index will be populated by inserting keys in strictly sorted 
  2216        ** order. In this case, instead of seeking within the b-tree as part
  2217        ** of every OP_IdxInsert opcode, an OP_SeekEnd is added before the
  2218        ** OP_IdxInsert to seek to the point within the b-tree where each key 
  2219        ** should be inserted. This is faster.
  2220        **
  2221        ** If any of the indexed columns use a collation sequence other than
  2222        ** BINARY, this optimization is disabled. This is because the user 
  2223        ** might change the definition of a collation sequence and then run
  2224        ** a VACUUM command. In that case keys may not be written in strictly
  2225        ** sorted order.  */
  2226        for(i=0; i<pSrcIdx->nColumn; i++){
  2227          const char *zColl = pSrcIdx->azColl[i];
  2228          if( sqlite3_stricmp(sqlite3StrBINARY, zColl) ) break;
  2229        }
  2230        if( i==pSrcIdx->nColumn ){
  2231          idxInsFlags = OPFLAG_USESEEKRESULT;
  2232          sqlite3VdbeAddOp1(v, OP_SeekEnd, iDest);
  2233        }
  2234      }
  2235      if( !HasRowid(pSrc) && pDestIdx->idxType==2 ){
  2236        idxInsFlags |= OPFLAG_NCHANGE;
  2237      }
  2238      sqlite3VdbeAddOp2(v, OP_IdxInsert, iDest, regData);
  2239      sqlite3VdbeChangeP5(v, idxInsFlags|OPFLAG_APPEND);
  2240      sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1+1); VdbeCoverage(v);
  2241      sqlite3VdbeJumpHere(v, addr1);
  2242      sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
  2243      sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
  2244    }
  2245    if( emptySrcTest ) sqlite3VdbeJumpHere(v, emptySrcTest);
  2246    sqlite3ReleaseTempReg(pParse, regRowid);
  2247    sqlite3ReleaseTempReg(pParse, regData);
  2248    if( emptyDestTest ){
  2249      sqlite3AutoincrementEnd(pParse);
  2250      sqlite3VdbeAddOp2(v, OP_Halt, SQLITE_OK, 0);
  2251      sqlite3VdbeJumpHere(v, emptyDestTest);
  2252      sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);
  2253      return 0;
  2254    }else{
  2255      return 1;
  2256    }
  2257  }
  2258  #endif /* SQLITE_OMIT_XFER_OPT */