站内搜索: 请输入搜索关键词
当前页面: 在线文档首页 > Java Platform, Enterprise Edition v5.0 API Specifications

SequenceGenerator (Java EE 5 SDK) - Java Platform, Enterprise Edition v5.0 API Specifications

Java EE 5 SDK

javax.persistence
Annotation Type SequenceGenerator


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

This annotation defines a primary key generator that may be referenced by name when a generator element is specified for the GeneratedValue annotation. A sequence generator may be specified on the entity class or on the primary key field or property. The scope of the generator name is global to the persistence unit (across all generator types).

   Example:

   @SequenceGenerator(name="EMP_SEQ", allocationSize=25)
 

Since:
Java Persistence 1.0

Required Element Summary
 String name
          (Required) A unique generator name that can be referenced by one or more classes to be the generator for primary key values.
 
Optional Element Summary
 int allocationSize
          (Optional) The amount to increment by when allocating sequence numbers from the sequence.
 int initialValue
          (Optional) The value from which the sequence object is to start generating.
 String sequenceName
          (Optional) The name of the database sequence object from which to obtain primary key values.
 

Element Detail

name

public abstract String name
(Required) A unique generator name that can be referenced by one or more classes to be the generator for primary key values.

sequenceName

public abstract String sequenceName
(Optional) The name of the database sequence object from which to obtain primary key values.

Defaults to a provider-chosen value.

Default:
""

initialValue

public abstract int initialValue
(Optional) The value from which the sequence object is to start generating.

Default:
1

allocationSize

public abstract int allocationSize
(Optional) The amount to increment by when allocating sequence numbers from the sequence.

Default:
50

Java EE 5 SDK

Submit a bug or feature

Copyright 2006 Sun Microsystems, Inc. All rights reserved.