如何使用注释应用唯一约束 [英] How to apply unique constraints using annotation

问题描述

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

我正在使用这些注释将数据输入到数据库表中.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 not allowed for this location.

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.

推荐答案

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

或者如果它是一个数据库生成的 ID你也可以这样做

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

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

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