org.apache.openjpa.jdbc.sql.Union Maven / Gradle / Ivy
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* to you 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
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*/
package org.apache.openjpa.jdbc.sql;
/**
* SQL UNION.
*
* @author Abe White
*/
public interface Union
extends SelectExecutor {
/**
* Return the selects that make up this union.
*/
public Select[] getSelects();
/**
* Get the union-level ordering, if any.
*/
public String getOrdering();
/**
* Whether this is a true UNION, rather than a logical combination of
* independent selects.
*/
public boolean isUnion();
/**
* Force the use of a series of standard selects rather than a true UNION.
*/
public void abortUnion();
/**
* Select data using the given selector.
*/
public void select(Selector selector);
/**
* A callback used to create the selects in a SQL union.
*/
public static interface Selector {
/**
* Populate the ith select in the union.
*/
public void select(Select sel, int i);
}
}