SecondaryTable (Java EE 5)

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SUMMARY: REQUIRED | OPTIONAL

DETAIL: ELEMENT

javax.persistence Annotation Type SecondaryTable

@Target(value=TYPE) @Retention(value=RUNTIME) public @interface SecondaryTable

Implements: Annotation

@Target(value=TYPE)
@Retention(value=RUNTIME)

此注释用于为带注释的实体类指定从属表格。指定一个或多个从属表格表示跨多个表格存储实体类的数据。

如果没有指定任何 SecondaryTable 注释，则假定实体的所有持久字段或属性都映射到主表格。如果没有指定任何主键连接列，则假设连接列引用主表格的主键列，并且其名称和类型与所引用的主表格的主键列相同。

示例 1：包含单个主键列的单个从属表格。

    @Entity
    @Table(name="CUSTOMER")
    @SecondaryTable(name="CUST_DETAIL", 
        pkJoinColumns=@PrimaryKeyJoinColumn(name="CUST_ID"))
    public class Customer { ... } 

示例 2：包含多个主键列的单个从属表格。

    @Entity
    @Table(name="CUSTOMER")
    @SecondaryTable(name="CUST_DETAIL",
        pkJoinColumns={
            @PrimaryKeyJoinColumn(name="CUST_ID"),
            @PrimaryKeyJoinColumn(name="CUST_TYPE")})
    public class Customer { ... }

since

Java Persistence 1.0

英文文档：

This annotation is used to specify a secondary table for the annotated entity class. Specifying one or more secondary tables indicates that the data for the entity class is stored across multiple tables.

If no SecondaryTable annotation is specified, it is assumed that all persistent fields or properties of the entity are mapped to the primary table. If no primary key join columns are specified, the join columns are assumed to reference the primary key columns of the primary table, and have the same names and types as the referenced primary key columns of the primary table.

 Example 1: Single secondary table with a single primary key column.

    @Entity
    @Table(name="CUSTOMER")
    @SecondaryTable(name="CUST_DETAIL", 
        pkJoinColumns=@PrimaryKeyJoinColumn(name="CUST_ID"))
    public class Customer { ... } 

    Example 2: Single secondary table with multiple primary key columns.

    @Entity
    @Table(name="CUSTOMER")
    @SecondaryTable(name="CUST_DETAIL",
        pkJoinColumns={
            @PrimaryKeyJoinColumn(name="CUST_ID"),
            @PrimaryKeyJoinColumn(name="CUST_TYPE")})
    public class Customer { ... }

Since:: Java Persistence 1.0

Required Element Summary
`String`	`name` (Required) The name of the table.

Optional Element Summary
`String`	`catalog` (Optional) The catalog of the table.
`PrimaryKeyJoinColumn[]`	`pkJoinColumns` (Optional) The columns that are used to join with the primary table.
`String`	`schema` (Optional) The schema of the table.
`UniqueConstraint[]`	`uniqueConstraints` (Optional) Unique constraints that are to be placed on the table.

Element Detail

abstract public String name()
（必须）表格名称。

英文文档：
name

public abstract String name

(Required) The name of the table.

abstract public String catalog()
（可选）表格种类。
默认为默认种类。

英文文档：
catalog

public abstract String catalog

(Optional) The catalog of the table.

Defaults to the default catalog.

Default:: ""

abstract public String schema()
（可选）表格模式。
默认为用户的默认模式。

英文文档：
schema

public abstract String schema

(Optional) The schema of the table.

Defaults to the default schema for user.

Default:: ""

abstract public PrimaryKeyJoinColumn[] pkJoinColumns()
（可选）用来连接主表格的列。
默认为与主表格中的主键列具有相同名称的列

英文文档：
pkJoinColumns

public abstract PrimaryKeyJoinColumn[] pkJoinColumns

(Optional) The columns that are used to join with the primary table.

Defaults to the column(s) of the same name(s) as the primary key column(s) in the primary table

Default:: {}

abstract public UniqueConstraint[] uniqueConstraints()
（可选）对表格设置的唯一约束。通常仅当表格生成生效时使用。除了应用 `Column` 和 `JoinColumn` 注释中指定的约束条件和主键映射引起的约束条件外，还应用这些约束条件。
默认为无额外限制。

英文文档：
uniqueConstraints

public abstract UniqueConstraint[] uniqueConstraints

(Optional) Unique constraints that are to be placed on the table. These are typically only used if table generation is in effect. These constraints apply in addition to any constraints specified by the Column and JoinColumn annotations and constraints entailed by primary key mappings.

Defaults to no additional constraints.