javax.persistence

注释类型 UniqueConstraint

@Target(value={})
 @Retention(value=RUNTIME)
public @interface UniqueConstraint

Specifies that a unique constraint is to be included in the generated DDL for a primary or secondary table.

    Example:
    @Entity
    @Table(
        name="EMPLOYEE",
        uniqueConstraints=
            @UniqueConstraint(columnNames={"EMP_ID", "EMP_NAME"})
    )
    public class Employee { ... }
 

从以下版本开始:

Java Persistence 1.0

必需元素概要

所需元素

限定符和类型	必需的元素和说明
String[]	columnNames (Required) An array of the column names that make up the constraint.

可选元素概要

可选元素

限定符和类型	可选元素和说明
String	name (Optional) Constraint name.

元素详细资料

columnNames

public abstract String[] columnNames

(Required) An array of the column names that make up the constraint.

返回:

String[]

name

public abstract String name

(Optional) Constraint name. A provider-chosen name will be chosen if a name is not specified.

返回:

String

从以下版本开始:

Java Persistence 2.0

默认值:

""