Jpa屏蔽表之间的主外键关联
Jpa根据实体对象生成的表，默认是带有主外键关系的。解决这个问题也简单。
通过标识注解 @ForeignKey(value = ConstraintMode.NO_CONSTRAINT) 屏蔽
这里使用5个实体演示
- User
- UserSeting
- Address
- Role
一对一，一对多，多对多都关系到了
实体类
@Entity
@Table(name = "user")
public class User implements Serializable {
private static final long serialVersionUID = 8175166175439387541L;
@Id
@Column(name = "id", columnDefinition = "INT(11) UNSIGNED COMMENT '用户id'")
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
@Column(columnDefinition = "varchar(20) COMMENT '昵称'")
private String name;
// 设置
@OneToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "id", referencedColumnName= "user_id", foreignKey = @ForeignKey(value = ConstraintMode.NO_CONSTRAINT))
private UserSeting userSeting;
// 角色
@ManyToMany(fetch = FetchType.LAZY)
@JoinTable(name = "user_role", joinColumns = {
@JoinColumn(name = "user_id", referencedColumnName = "id")
}, inverseJoinColumns = {
@JoinColumn(name = "role_id", referencedColumnName = "id")
}, foreignKey = @ForeignKey(value = ConstraintMode.NO_CONSTRAINT), inverseForeignKey = @ForeignKey(value = ConstraintMode.NO_CONSTRAINT))
private Set<Role> roles = new HashSet<>();
// 地址
@OneToMany(fetch = FetchType.LAZY)
@JoinColumn(name = "user_id", referencedColumnName = "id", foreignKey = @ForeignKey(value = ConstraintMode.NO_CONSTRAINT))
private Set<Address> addresses = new HashSet<>();
}
@Entity
@Table(name = "user_seting")
public class UserSeting implements Serializable {
/**
*
*/
private static final long serialVersionUID = -1007318207008996614L;
@Id
@Column(name = "id", columnDefinition = "INT(11) unsigned COMMENT '设置id'")
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
@Column(columnDefinition = "TINYINT(1) unsigned COMMENT '是否接受通知'")
private Boolean notify;
@OneToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "user_id", referencedColumnName = "id", unique = true, nullable = false,
foreignKey = @ForeignKey(value = ConstraintMode.NO_CONSTRAINT))
private User user;
}
@Entity
@Table(name = "address", indexes = {
@Index(columnList = "user_id", unique = false)
})
public class Address implements Serializable{
private static final long serialVersionUID = -544913276641093655L;
@Id
@Column(name = "id", columnDefinition = "INT(11) UNSIGNED COMMENT '地址id'")
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
@Column(columnDefinition = "VARCHAR(500) COMMENT '详细地址'")
private String name;
@ManyToOne(fetch = FetchType.LAZY)
@JoinColumn(name = "user_id", referencedColumnName = "id", nullable = false,
foreignKey = @ForeignKey(value = ConstraintMode.NO_CONSTRAINT))
private User user;
}
@Entity
@Table(name = "role")
public class Role {
@Id
@Column(name = "id", columnDefinition = "INT(11) UNSIGNED COMMENT '角色id'")
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Integer id;
@Column(columnDefinition = "varchar(20) COMMENT '角色名称'")
private String name;
@ManyToMany(fetch = FetchType.LAZY)
@JoinTable(name = "user_role", joinColumns = {
@JoinColumn(name = "role_id", referencedColumnName = "id")
}, inverseJoinColumns = {
@JoinColumn(name = "user_id", referencedColumnName = "id")
}, foreignKey = @ForeignKey(value = ConstraintMode.NO_CONSTRAINT), inverseForeignKey = @ForeignKey(value = ConstraintMode.NO_CONSTRAINT))
private Set<User> users = new HashSet<>();
}
生成的表结构
没有主外键关系，很干净
CREATE TABLE `user` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT COMMENT '用户id',
`name` varchar(20) DEFAULT NULL COMMENT '昵称',
`version` int(11) unsigned NOT NULL COMMENT '版本号',
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
CREATE TABLE `user_seting` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT COMMENT '设置id',
`notify` tinyint(1) unsigned DEFAULT NULL COMMENT '是否接受通知',
`user_id` int(11) unsigned NOT NULL COMMENT '用户id',
PRIMARY KEY (`id`),
UNIQUE KEY `UK_rdchrax5rp1m1y4kpax285krw` (`user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
CREATE TABLE `address` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT COMMENT '地址id',
`name` varchar(500) DEFAULT NULL COMMENT '详细地址',
`user_id` int(11) unsigned NOT NULL COMMENT '用户id',
PRIMARY KEY (`id`),
KEY `IDX7rod8a71yep5vxasb0ms3osbg` (`user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
CREATE TABLE `role` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT COMMENT '角色id',
`name` varchar(20) DEFAULT NULL COMMENT '角色名称',
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
CREATE TABLE `user_role` (
`user_id` int(11) unsigned NOT NULL COMMENT '用户id',
`role_id` int(11) unsigned NOT NULL COMMENT '角色id',
PRIMARY KEY (`role_id`,`user_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
总结
注解加持就完事儿了，不是添加在 @JoinColumn 就是添加在 @JoinTable
@JoinColumn(foreignKey = @ForeignKey(value = ConstraintMode.NO_CONSTRAINT))
@JoinTable(foreignKey = @ForeignKey(value = ConstraintMode.NO_CONSTRAINT), inverseForeignKey = @ForeignKey(value = ConstraintMode.NO_CONSTRAINT))
jpa + querydsl 是真的香
