映射 OneToOne 、OneToMany

OneToMany   由多的一方维护关系  既(Many方)

public class Huitie implements Serializable {
 @OneToMany
    @JoinColumn(name = "huifutie_id", referencedColumnName = "id", insertable = false, updatable = false)
    private List<Pinglunren> pinglunrens;
}

只在一方映射,另外一方不写的时候

维护关系方  添加 注解 @JoinColumn(name = "user_id", referencedColumnName = "id")

name 属性 为多的一方(Pinglunren) 的外键在数据库里面的名字 ,referencedColumnName 为映射另一方(Huitie )的主键 id

如果出现  

public class Huitie implements Serializable {

@Column(name = "user_id")
private Long userId;

@OneToOne(fetch = FetchType.EAGER)
@JoinColumn(name = "user_id", referencedColumnName = "id", insertable = false, updatable = false)
private User user;
}

映射字段一样的,需要添加  insertable = false, updatable = false,否则会不知道应该是映射属性 还是 对象

OneToOne   由自己维护关系  

name 属性 为自己(Huitie)在数据库里面的外键名字     referencedColumnName 为User 的主键id

    
 @OneToMany
    @JoinColumn(name = "publish_pay_id", referencedColumnName = "id", insertable = false,         updatable = false)
    private List<PublishBuy> publishBuys1;



映射后,查询时,可以通过  .any()  设置映射后,可以设置查询集合的条件,
注意如果映射集合的条件不满足,那么当前对象和对象里面映射的集合对象都不会返回

QPublishPay qPublishPay = QPublishPay.publishPay;
        List<PublishPay> publishPays = jpaQueryFactory
                .selectFrom(qPublishPay)
                .where(qPublishPay.userid.eq(userId)
                .and(qPublishPay.publishBuys1.any().status.eq("2")))
                .fetch();
        return ServiceResponse.createBySuccess(publishPays);

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转载自blog.csdn.net/qq_42383787/article/details/86241424