forked from dolthub/go-mysql-server
/
empty_table.go
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/
empty_table.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/Sndav/go-mysql-server/sql"
// EmptyTable is a node representing an empty table.
var EmptyTable = new(emptyTable)
type emptyTable struct{}
func (emptyTable) Schema() sql.Schema { return nil }
func (emptyTable) Children() []sql.Node { return nil }
func (emptyTable) Resolved() bool { return true }
func (e *emptyTable) String() string { return "EmptyTable" }
func (emptyTable) RowIter(ctx *sql.Context, row sql.Row) (sql.RowIter, error) {
return sql.RowsToRowIter(), nil
}
// WithChildren implements the Node interface.
func (e *emptyTable) WithChildren(children ...sql.Node) (sql.Node, error) {
if len(children) != 0 {
return nil, sql.ErrInvalidChildrenNumber.New(e, len(children), 0)
}
return e, nil
}