Java JPA 中的多个唯一约束
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/3404853/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
Multiple unique constraints in JPA
提问by Jacob
Is there a way to specify using JPA that there should be multiple unique constraints on different sets of columns?
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 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.
我看到了一个特定于休眠的注释，但我试图避免供应商特定的解决方案，因为我们仍在决定休眠和 datanucleus 之间。
采纳答案by Bozho
The @Table's attribute uniqueConstraintsactually accepts an array of these. Your example is just a shorthand for an array with a single element. Otherewise it would look like:
所述@Table的属性uniqueConstraints实际接受的这些阵列。您的示例只是具有单个元素的数组的简写。否则它看起来像：
@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.
当唯一约束仅基于一个字段时，您可以@Column(unique=true)在该列上使用。
