I have encountered a bug in using Spring Data Jpa. Specifically,when @OneToMany was used to maintain a one-to-many relationship, lazy loading was effective.However,it may passively trigger the cascading query without using the cascading property. My…

Project, project_id @OneToMany(mappedBy = "project") private Set<Ap> apSet =new HashSet<Ap>(); Ap, ap_id @ManyToOne(fetch = FetchType.EAGER) @JoinColumn( name = "project_id",nullable = false) private Project project; 注意不要有c…

oneToMany 使用: 示例:Employee与Phone为例. 1.类定义如下: package com.vrvwh.wh01.domain; import javax.persistence.*; import java.util.HashSet; import java.util.Set; /** * Created by Administrator on 2015/3/5. */ @Entity public class Employee { private long id; pri…

自己是直接查出来然后利用set去重(自己感觉不是太好,不过能达到目的) List<CampaignDashboardDimensionDo> list = query.getResultList();Set<CampaignDashboardDimensionDo> set=new HashSet<>(list);如有更好的方法,希望大佬留言,谢谢…

WebSphere 7 & Javax/Persistence/OneToMany.OrphanRemoval() Error 文章出处:http://www.mkyong.com/websphere/websphere-7-javaxpersistenceonetomany-orphanremoval-error/ Problem In Hibernate development, contains a model class with JPA @OneToMany annotation :…

环境:Spring Data Jpa,hibernate或者其他jpa实现也是一样的:Spring Boot 场景:User和Role,一个User要对应多个Role. 第一种方式,没有中间关系表,直接在role表中添加一个user_id字段 User: import javax.persistence.*; import javax.validation.constraints.NotNull; import java.util.HashSet; import java.util.Set; /…

在Jpa中如果设置@OneToMany,但使用的时候,如果没有赋值,会报异常出现,这时只需要实例化一个空数组即可, 但类型一定要对应: 实例如下: newField.setxxxxxList(new ArrayList<xxxxx>(){}); 切记.切记…

JPA实体关系映射:@ManyToMany多对多关系.@OneToMany@ManyToOne一对多多对一关系和@OneToOne的深度实例解析 今天程序中遇到的错误一 org.hibernate.AnnotationException: Collection has neither generic type or OneToMany.targetEntity() defined: com.hibernate.SubStation.bays 错误解决方法 org.hibernate.Annota…

JPA总结——实体关系映射(一对多@OneToMany) 注意:本文出自“阿飞”的博客,如果要转载本文章,请与作者联系! 并注明来源: http://blog.sina.com.cn/s/blog_49fd52cf0100scql.html 一对多模型(单向)说明:一个客户对应多个地址,通过客户可以获得该客户的多个地址的信息.客户和地址是一对多的关系,并且客户与地址是单向关联的关系. 映射策略# 外键关联:两个表的关系定义在一个表中:# 表关联:两个表的关系单独定义一个表中通过一个中间表来关联.…

顾名思义,@OneToMany.@ManyToOne这两个注解就是处理一对多,多对一的关系 这两个注解是成双成对的,有了@OneToMany,一定会配置一个@ManyToOne OneToMany设置 设置OneToMany的具体方法如下: @Entity public class OrderEntity { @Id //... private String id; @OneToMany(cascade = CascadeType.ALL, fetch = FetchType.EAGER, ma…