/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* License: GNU Lesser General Public License (LGPL), version 2.1 or later.
* See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
*/
package org.hibernate.dialect;
/**
* Defines how we need to reference columns in the group-by, having, and order-by
* clauses.
*
* @author Steve Ebersole
*/
public enum ResultColumnReferenceStrategy {
/**
* This strategy says to reference the result columns by the qualified column name
* found in the result source. This strategy is not strictly allowed by ANSI SQL
* but is Hibernate's legacy behavior and is also the fastest of the strategies; thus
* it should be used if supported by the underlying database.
*/
SOURCE,
/**
* For databases which do not support {@link #SOURCE}, ANSI SQL defines two allowable
* approaches. One is to reference the result column by the alias it is given in the
* result source (if it is given an alias). This strategy says to use this approach.
* <p/>
* The other QNSI SQL compliant approach is {@link #ORDINAL}.
*/
ALIAS,
/**
* For databases which do not support {@link #SOURCE}, ANSI SQL defines two allowable
* approaches. One is to reference the result column by the ordinal position at which
* it appears in the result source. This strategy says to use this approach.
* <p/>
* The other QNSI SQL compliant approach is {@link #ALIAS}.
*/
ORDINAL;
/**
* Resolves the strategy by name, in a case insensitive manner. If the name cannot be resolved, {@link #SOURCE}
* is returned as the default.
*
* @param name The strategy name to resolve
*
* @return The resolved strategy
*/
public static ResultColumnReferenceStrategy resolveByName(String name) {
if ( ALIAS.name().equalsIgnoreCase( name ) ) {
return ALIAS;
}
else if ( ORDINAL.name().equalsIgnoreCase( name ) ) {
return ORDINAL;
}
else {
return SOURCE;
}
}
}