Version (Java EE 5 SDK)

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Java EE 5 SDK

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摘要: REQUIRED | OPTIONAL

详细信息: ELEMENT

javax.persistence Annotation Type Version

@Target(value={METHOD,FIELD}) @Retention(value=RUNTIME) public @interface Version

This annotation specifies the version field or property of an entity class that serves as its optimistic lock value. The version is used to ensure integrity when performing the merge operation and for optimistic concurrency control.

Only a single Version property or field should be used per class; applications that use more than one Version property or field will not be portable.

The Version property should be mapped to the primary table for the entity class; applications that map the Version property to a table other than the primary table will not be portable.

The following types are supported for version properties: int, Integer, short, Short, long, Long, Timestamp.

    Example:

    @Version
    @Column(name="OPTLOCK")
    protected int getVersionNum() { return versionNum; }

从以下版本开始:: Java Persistence 1.0

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