org.hibernate.engine.FetchStyle Maven / Gradle / Ivy
/*
* Hibernate, Relational Persistence for Idiomatic Java
*
* Copyright (c) 2011, Red Hat Inc. or third-party contributors as
* indicated by the @author tags or express copyright attribution
* statements applied by the authors. All third-party contributions are
* distributed under license by Red Hat Inc.
*
* This copyrighted material is made available to anyone wishing to use, modify,
* copy, or redistribute it subject to the terms and conditions of the GNU
* Lesser General Public License, as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this distribution; if not, write to:
* Free Software Foundation, Inc.
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*/
package org.hibernate.engine;
/**
* Enumeration of values describing HOW fetching should occur.
*
* @author Steve Ebersole
* @see FetchTiming
*/
public enum FetchStyle {
/**
* Performs a separate SQL select to load the indicated data. This can either be eager (the second select is
* issued immediately) or lazy (the second select is delayed until the data is needed).
*/
SELECT,
/**
* Inherently an eager style of fetching. The data to be fetched is obtained as part of an SQL join.
*/
JOIN,
/**
* Initializes a number of indicated data items (entities or collections) in a series of grouped sql selects
* using an in-style sql restriction to define the batch size. Again, can be either eager or lazy.
*/
BATCH,
/**
* Performs fetching of associated data (currently limited to only collections) based on the sql restriction
* used to load the owner. Again, can be either eager or lazy.
*/
SUBSELECT
}