Use eclipselink.batch
to supply EclipseLink with batching information so subsequent queries of related objects can be optimized in batches, instead of being retrieved one-by-one or in one large joined read.
Values
This query hint accepts a single-valued, relationship path expression.
Usage
Using the eclipselink.batch
hint is more efficient than joining, because EclipseLink avoids reading duplicate data.
You can only batch queries that have a single object in the select clause.
Valid values: a single-valued relationship path expression.
Use dot notation to access nested attributes. For example, to batch-read an employee's manager's address, use |
Examples
Example 4-1 shows how to use this hint in a JPA query.
Example 4-1 Using batch in a JPA Query
import org.eclipse.persistence.config.HintValues; import org.eclipse.persistence.config.QueryHints; query.setHint("eclipselink.batch", "e.address");
Example 4-2 shows how to use this hint with the @QueryHint
annotation.
Example 4-2 Using batch in a @QueryHint Annotation
import org.eclipse.persistence.config.HintValues; import org.eclipse.persistence.config.QueryHints; @QueryHint(name=QueryHints.BATCH, value="e.address");
See Also
For more information, see:
"EclipseLink" JPA Query Hints
http://wiki.eclipse.org/EclipseLink/UserGuide/JPA/Basic_JPA_Development/Querying/Query_Hints
"Querying" in Solutions Guide for EclispeLink