GenerationType (Java EE 5 SDK)

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Java EE 5 SDK

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摘要: 嵌套 | ENUM 构造器 | 字段 | 方法

详细信息: ENUM 构造器 | 字段 | 方法

javax.persistence Enum GenerationType

java.lang.Object
  java.lang.Enum<GenerationType>
      javax.persistence.GenerationType

所有已实现的接口:: Serializable, Comparable<GenerationType>

public enum GenerationType
extends Enum<GenerationType>

Defines the types of primary key generation.

从以下版本开始:: Java Persistence 1.0

Enum 常量摘要
`AUTO` Indicates that the persistence provider should pick an appropriate strategy for the particular database.
`IDENTITY` Indicates that the persistence provider must assign primary keys for the entity using database identity column.
`SEQUENCE` Indicates that the persistence provider must assign primary keys for the entity using database sequence column.
`TABLE` Indicates that the persistence provider must assign primary keys for the entity using an underlying database table to ensure uniqueness.

方法摘要
`static GenerationType`	`valueOf(String name)` Returns the enum constant of this type with the specified name.
`static GenerationType[]`	`values()` Returns an array containing the constants of this enum type, in the order they're declared.

类方法继承 java.lang.Enum
`clone, compareTo, equals, getDeclaringClass, hashCode, name, ordinal, toString, valueOf`

类方法继承 java.lang.Object
`finalize, getClass, notify, notifyAll, wait, wait, wait`

Enum 常量详细信息

TABLE

public static final GenerationType TABLE

Indicates that the persistence provider must assign primary keys for the entity using an underlying database table to ensure uniqueness.

SEQUENCE

public static final GenerationType SEQUENCE

Indicates that the persistence provider must assign primary keys for the entity using database sequence column.

IDENTITY

public static final GenerationType IDENTITY

Indicates that the persistence provider must assign primary keys for the entity using database identity column.

AUTO

public static final GenerationType AUTO

Indicates that the persistence provider should pick an appropriate strategy for the particular database. The AUTO generation strategy may expect a database resource to exist, or it may attempt to create one. A vendor may provide documentation on how to create such resources in the event that it does not support schema generation or cannot create the schema resource at runtime.

方法详细信息

values

public static final GenerationType[] values()

Returns an array containing the constants of this enum type, in the order they're declared. This method may be used to iterate over the constants as follows:

for(GenerationType c : GenerationType.values())
        System.out.println(c);

返回:: an array containing the constants of this enum type, in the order they're declared

valueOf

public static GenerationType valueOf(String name)

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.)

参数:: name - the name of the enum constant to be returned.
返回:: the enum constant with the specified name
抛出异常:: IllegalArgumentException - if this enum type has no constant with the specified name

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