/
naturaljoin.go
executable file
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/
naturaljoin.go
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// Copyright 2020-2021 Dolthub, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package plan
import "github.com/Rock-liyi/p2pdb-store/sql"
// NaturalJoin is a join that automatically joins by all the columns with the
// same name.
// NaturalJoin is a placeholder node, it should be transformed into an INNER
// JOIN during analysis.
type NaturalJoin struct {
BinaryNode
}
// NewNaturalJoin returns a new NaturalJoin node.
func NewNaturalJoin(left, right sql.Node) *NaturalJoin {
return &NaturalJoin{BinaryNode{left, right}}
}
// RowIter implements the Node interface.
func (NaturalJoin) RowIter(*sql.Context, sql.Row) (sql.RowIter, error) {
panic("NaturalJoin is a placeholder, RowIter called")
}
// Schema implements the Node interface.
func (NaturalJoin) Schema() sql.Schema {
panic("NaturalJoin is a placeholder, Schema called")
}
// Resolved implements the Node interface.
func (NaturalJoin) Resolved() bool { return false }
func (j NaturalJoin) String() string {
pr := sql.NewTreePrinter()
_ = pr.WriteNode("NaturalJoin")
_ = pr.WriteChildren(j.left.String(), j.right.String())
return pr.String()
}
// WithChildren implements the Node interface.
func (j *NaturalJoin) WithChildren(children ...sql.Node) (sql.Node, error) {
if len(children) != 2 {
return nil, sql.ErrInvalidChildrenNumber.New(j, len(children), 2)
}
return NewNaturalJoin(children[0], children[1]), nil
}