com.hazelcast.org.apache.calcite.schema.ExtensibleTable Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to you under the Apache License, Version 2.0
* (the "License"); you may not use this file except in com.hazelcast.com.liance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.com.hazelcast.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 com.hazelcast.org.apache.calcite.schema;
import com.hazelcast.org.apache.calcite.rel.type.RelDataTypeField;
import java.util.List;
/**
* Table whose row type can be extended to include extra fields.
*
* In some storage systems, especially those with "late schema", there may
* exist columns that have values in the table but which are not declared in
* the table schema. However, a particular query may wish to reference these
* columns as if they were defined in the schema. Calling the {@link #extend}
* method creates a temporarily extended table schema.
*
*
If the table implements extended interfaces such as
* {@link com.hazelcast.org.apache.calcite.schema.ScannableTable},
* {@link com.hazelcast.org.apache.calcite.schema.FilterableTable} or
* {@link com.hazelcast.org.apache.calcite.schema.ProjectableFilterableTable}, you may wish
* to make the table returned from {@link #extend} implement these interfaces
* as well.
*/
public interface ExtensibleTable extends Table {
/** Returns a table that has the row type of this table plus the given
* fields. */
Table extend(List fields);
/** Returns the starting offset of the first extended column, which may differ
* from the field count when the table stores metadata columns that are not
* counted in the row-type field count. */
int getExtendedColumnOffset();
}