- All Implemented Interfaces:
Serializable
,Comparable<BatchFetchType>
,java.lang.constant.Constable
Enum used with the BatchFetch annotation, or "eclipselink.batch.type" query hint.
This can be specified on a mapping or query to configure the type of batch reading to be used.
- Since:
- EclipseLink 2.1
- See Also:
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Nested Class Summary
Nested classes/interfaces inherited from class java.lang.Enum
Enum.EnumDesc<E extends Enum<E>>
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Enum Constant Summary
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Method Summary
Modifier and TypeMethodDescriptionstatic BatchFetchType
Returns the enum constant of this type with the specified name.static BatchFetchType[]
values()
Returns an array containing the constants of this enum type, in the order they are declared.
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Enum Constant Details
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JOIN
This is the default form of batch reading. The original query's selection criteria is joined with the batch query. -
EXISTS
This uses an SQL EXISTS and a sub-select in the batch query instead of a join. This has the advantage of not requiring an SQL DISTINCT which can have issues with LOBs, or may be more efficient for some types of queries or on some databases. -
IN
This uses an SQL IN clause in the batch query passing in the source object Ids. This has the advantage of only selecting the objects not already contained in the cache, and can work better with cursors, or if joins cannot be used. This may only work for singleton Ids on some databases.
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Method Details
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values
Returns an array containing the constants of this enum type, in the order they are declared.- Returns:
- an array containing the constants of this enum type, in the order they are declared
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valueOf
Returns the enum constant of this type with the specified name. The string must match exactly an identifier used to declare an enum constant in this type. (Extraneous whitespace characters are not permitted.)- Parameters:
name
- the name of the enum constant to be returned.- Returns:
- the enum constant with the specified name
- Throws:
IllegalArgumentException
- if this enum type has no constant with the specified nameNullPointerException
- if the argument is null
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