如何使用注释应用唯一约束

发布于 2024-12-05 19:43:36 字数 229 浏览 0 评论 0原文

@Column(name = "userId")
    @UniqueConstraint
    private Integer userId;

我正在使用这些注释将数据输入数据库表。我想让 userId 字段成为唯一字段。但是当我这样做时，它向我显示错误 @UniqueConstraints is disallowed for this location.

原文

@Column(name = "userId")
    @UniqueConstraint
    private Integer userId;

I am using these annotation for entering data into database table.
i want to make userId field unique field. but when i am doing like it it is showing me error @UniqueConstraints is disallowed for this location.

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寄人书 2024-12-12 19:43:36

@Column(name = "userId",unique=true)

或者如果它是数据库生成的 ID 你也可以这样做

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Integer id;

@Column(name = "userId",unique=true)

or if its an DB generated ID you can also do this

    @Id
    @GeneratedValue(strategy=GenerationType.AUTO)
    private Integer id;

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请恋爱 2024-12-12 19:43:36

下面是如何使用 @UniqueConstraint 的示例：

@Entity
@Table(name = "contact", 
  uniqueConstraints = @UniqueConstraint(columnNames = {"name", "company_id"}))
public class Contact {
  ...
}

这指定“name”列和“company_id”列的组合将是唯一的。

Here's an example of how to use @UniqueConstraint:

@Entity
@Table(name = "contact", 
  uniqueConstraints = @UniqueConstraint(columnNames = {"name", "company_id"}))
public class Contact {
  ...
}

This specifies that the combination of the "name" column and the "company_id" column will be unique.

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感情洁癖 2024-12-12 19:43:36

这是 Hibernate doc< 的解释/a> 版本 3.5 用于 @UniqueConstraint 定义。

 @Entity
    @Table(name="tbl_sky",uniqueConstraints = {@UniqueConstraint(columnNames={"month", "day"})})
    public class Sky implements Serializable {
       ...
    }

这是针对 Hibernate 4.3 @UniqueConstraint 的示例

And this is the explanation of the Hibernate doc version 3.5 for @UniqueConstraint definition.

 @Entity
    @Table(name="tbl_sky",uniqueConstraints = {@UniqueConstraint(columnNames={"month", "day"})})
    public class Sky implements Serializable {
       ...
    }

and this is for Hibernate 4.3 example for @UniqueConstraint

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