github.com/XiaoMi/Gaea@v1.2.5/proxy/plan/plan_delete.go (about)

     1  // Copyright 2019 The Gaea Authors. All Rights Reserved.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package plan
    16  
    17  import (
    18  	"fmt"
    19  
    20  	"github.com/XiaoMi/Gaea/mysql"
    21  	"github.com/XiaoMi/Gaea/parser/ast"
    22  	"github.com/XiaoMi/Gaea/proxy/router"
    23  	"github.com/XiaoMi/Gaea/util"
    24  )
    25  
    26  // DeletePlan is the plan for delete statement
    27  type DeletePlan struct {
    28  	basePlan
    29  	*TableAliasStmtInfo
    30  
    31  	stmt *ast.DeleteStmt
    32  	sqls map[string]map[string][]string
    33  }
    34  
    35  // NewDeletePlan constructor of DeletePlan
    36  func NewDeletePlan(stmt *ast.DeleteStmt, db, sql string, r *router.Router) *DeletePlan {
    37  	return &DeletePlan{
    38  		TableAliasStmtInfo: NewTableAliasStmtInfo(db, sql, r),
    39  		stmt:               stmt,
    40  	}
    41  }
    42  
    43  // ExecuteIn implement Plan
    44  func (p *DeletePlan) ExecuteIn(reqCtx *util.RequestContext, sess Executor) (*mysql.Result, error) {
    45  	sqls := p.sqls
    46  	if sqls == nil {
    47  		return nil, fmt.Errorf("SQL has not generated")
    48  	}
    49  
    50  	if len(sqls) == 0 {
    51  		return nil, nil
    52  	}
    53  
    54  	rs, err := sess.ExecuteSQLs(reqCtx, sqls)
    55  	if err != nil {
    56  		return nil, fmt.Errorf("execute in UpdatePlan error: %v", err)
    57  	}
    58  
    59  	r, err := MergeExecResult(rs)
    60  
    61  	if err != nil {
    62  		return nil, fmt.Errorf("merge update result error: %v", err)
    63  	}
    64  
    65  	return r, nil
    66  }
    67  
    68  // HandleDeletePlan build a DeletePlan
    69  func HandleDeletePlan(p *DeletePlan) error {
    70  	if err := handleDeleteTableRefs(p); err != nil {
    71  		return fmt.Errorf("handle From error: %v", err)
    72  	}
    73  
    74  	if err := handleDeleteWhere(p); err != nil {
    75  		return fmt.Errorf("handle Where error: %v", err)
    76  	}
    77  
    78  	if err := handleDeleteOrderBy(p); err != nil {
    79  		return fmt.Errorf("handle OrderBy error: %v", err)
    80  	}
    81  
    82  	// Limit clause does not need to handle
    83  
    84  	// handle global table
    85  	if err := postHandleGlobalTableRouteResultInModify(p.StmtInfo); err != nil {
    86  		return fmt.Errorf("post handle global table error: %v", err)
    87  	}
    88  
    89  	sqls, err := generateShardingSQLs(p.stmt, p.GetRouteResult(), p.router)
    90  	if err != nil {
    91  		return fmt.Errorf("generate sqls error: %v", err)
    92  	}
    93  
    94  	p.sqls = sqls
    95  	return nil
    96  }
    97  
    98  func handleDeleteTableRefs(p *DeletePlan) error {
    99  	tableRefs := p.stmt.TableRefs
   100  	if tableRefs == nil {
   101  		return nil
   102  	}
   103  
   104  	join := tableRefs.TableRefs
   105  	if join == nil {
   106  		return nil
   107  	}
   108  
   109  	if join.Right != nil {
   110  		return fmt.Errorf("does not support update multiple tables in sharding")
   111  	}
   112  
   113  	return handleJoin(p.TableAliasStmtInfo, join)
   114  }
   115  
   116  func handleDeleteWhere(p *DeletePlan) error {
   117  	stmt := p.stmt
   118  	if stmt.Where == nil {
   119  		return nil
   120  	}
   121  
   122  	has, result, decorator, err := handleComparisonExpr(p.TableAliasStmtInfo, stmt.Where)
   123  	if err != nil {
   124  		return fmt.Errorf("rewrite Where error: %v", err)
   125  	}
   126  	if has {
   127  		p.GetRouteResult().Inter(result)
   128  	}
   129  	stmt.Where = decorator
   130  	return nil
   131  
   132  }
   133  
   134  func handleDeleteOrderBy(p *DeletePlan) error {
   135  	order := p.stmt.Order
   136  	if order == nil {
   137  		return nil
   138  	}
   139  
   140  	for _, item := range order.Items {
   141  		columnExpr, ok := item.Expr.(*ast.ColumnNameExpr)
   142  		if !ok {
   143  			return fmt.Errorf("ByItem.Expr is not a ColumnNameExpr")
   144  		}
   145  
   146  		rule, need, isAlias, err := NeedCreateColumnNameExprDecoratorInField(p.TableAliasStmtInfo, columnExpr)
   147  		if err != nil {
   148  			return err
   149  		}
   150  
   151  		if need {
   152  			decorator := CreateColumnNameExprDecorator(columnExpr, rule, isAlias, p.GetRouteResult())
   153  			item.Expr = decorator
   154  		}
   155  	}
   156  
   157  	return nil
   158  }