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SUMMARY: REQUIRED | OPTIONAL

DETAIL: ELEMENT

javax.persistence Annotation Type Version

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

Implements: Annotation

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

此注释指定实体类的版本字段或属性，以用作乐观锁定值。此版本用于确保执行合并操作时的完整性以及乐观并发控制。

每个类只能使用一个 Version 属性或字段；使用多个 Version 属性或字段的应用程序将不可移植。

Version 属性应该映射到实体类的主表格；将 Version 属性映射到主表格以外的表格的应用程序将不可移植。

版本属性支持以下类型：int、Integer、short、Short、long、Long、Timestamp。

示例：


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

since

Java Persistence 1.0

英文文档：

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; }

Since:: Java Persistence 1.0