github.com/dolthub/go-mysql-server@v0.18.0/memory/dual_table.go (about)

     1  // Copyright 2023 Dolthub, Inc.
     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 memory
    16  
    17  import (
    18  	"github.com/dolthub/go-mysql-server/sql"
    19  	"github.com/dolthub/go-mysql-server/sql/types"
    20  )
    21  
    22  const DualTableName = ""
    23  
    24  var DualTableSchema = sql.NewPrimaryKeySchema(sql.Schema{
    25  	{Name: "", Source: DualTableName, Type: types.LongText, Nullable: false},
    26  })
    27  
    28  // NewDualTable creates the dual table, which is used by the engine for queries with no tables specified, or the
    29  // `dual` table specified. This table is never supplied by integrators, but always by this stand-in implementation.
    30  func NewDualTable() *Table {
    31  	tbl := NewTable(nil, DualTableName, DualTableSchema, nil)
    32  	tbl.ignoreSessionData = true
    33  	part := []byte{0}
    34  	tbl.data.partitions = map[string][]sql.Row{
    35  		string(part): {{"x"}},
    36  	}
    37  	tbl.data.partitionKeys = [][]byte{part}
    38  
    39  	return tbl
    40  }