Module eclipselink

Package org.eclipse.persistence.annotations

Annotation Interface BatchFetch

@Target({METHOD,FIELD})
@Retention(RUNTIME)
public @interface BatchFetch

A BatchFetch annotation can be used on any relationship mapping (OneToOne, ManyToOne, OneToMany, ManyToMany, ElementCollection, BasicCollection, BasicMap). It allows the related objects to be batch read in a single query. Batch fetching can also be set at the query level, and it is normally recommended to do so as all queries may not require batching.

Author:

James Sutherland

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
int	size	Define the default batch fetch size.
BatchFetchType	value	The type of batch-fetch to use.

Element Details

value

BatchFetchType value

The type of batch-fetch to use. Either BatchFetchType.JOIN, BatchFetchType.EXISTS or BatchFetchType.IN.

BatchFetchType.JOIN is the default.

Default:

JOIN

size

int size

Define the default batch fetch size. This is only used for BatchFetchType.IN type batch reading and defines the number of keys used in each IN clause.

The default size is 256, or the query's pageSize for cursor queries.

Default:

-1