JPA中的多个唯一约束 [英] Multiple unique constraints in JPA

问题描述

有没有办法使用JPA指定在不同的列集上应该有多个唯一约束？

  @Entity 
 @Table（name =person，
 uniqueConstraints = @ UniqueConstraint（columnNames = {code，uid}））
 public class Person {
 // Unique在代码和uid 
公共字符串代码; 
 public String uid; 
 
 //用户名
的唯一性public String username; 
 
公共字符串名称; 
 public String email; 
} 
  

我已经看到了一个hibernate特定的注释，但我试图避免供应商特定的解决方案因为我们仍然在决定hibernate和datanucleus之间。

>的属性 uniqueConstraints 实际上接受这些数组。你的例子只是一个单个元素的数组的缩写。不然的话，它看起来像：

  @Table（name =person，uniqueConstraints = {
 @UniqueConstraint（columnNames = {code，uid}），
 @UniqueConstraint（columnNames = {anotherField，uid}）
}）
  pre> 
 
 
只要唯一约束仅基于一个字段，就可以使用 @Column（unique = true）在那一栏。  
Is there a way to specify using JPA that there should be multiple unique constraints on different sets of columns?
@Entity
@Table(name="person", 
       uniqueConstraints=@UniqueConstraint(columnNames={"code", "uid"}))
public class Person {
    // Unique on code and uid
    public String code;
    public String uid;

    // Unique on username
    public String username;

    public String name;
    public String email;
}
I have seen a hibernate specific annotation but I am trying to avoid vendor specific solutions as we are still deciding between hibernate and datanucleus.
解决方案
The @Table's attribute uniqueConstraints actually accepts an array of these. Your example is just a shorthand for an array with a single element. Otherewise it would look like:
@Table(name="person",  uniqueConstraints={
   @UniqueConstraint(columnNames={"code", "uid"}),
   @UniqueConstraint(columnNames={"anotherField", "uid"})
})
Whenever the unique constraint is based only on one field, you can use @Column(unique=true) on that column. 

                        
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