mappedby

hibernate and mappedBy: Is it possible to automatically set foreign key without setting bidirectional relationship among objects?

由 我只是一个虾纸丫 提交于 2021-02-17 03:47:29
问题 Welcome, I have 2 classes: Conversation and Question. One Conversation have many questions. Conversation.java: package com.jcg.jpa.mappedBy; import java.io.Serializable; import java.util.ArrayList; import java.util.Collection; import javax.persistence.CascadeType; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType; import javax.persistence.Id; import javax

How to delete a row in join table with JPA

由 江枫思渺然 提交于 2020-01-13 10:12:09
问题 I have the model below : an article can have some tags and a tag can be on some articles. So it is a many-to-many relationship with 3 tables : ARTICLE ARTICLE_TAG TAG When I delete a tag, I want to delete : the tag in TAG all relations between the tag and the articles tagged in ARTICLE_TAG But I don't want to delete the articles in ARTICLE of course. How can I do that ? I try this, but it doesn't work : Session session = HibernateUtil.getSessionFactory().getCurrentSession(); for (Article

Grails v3.3.9 GORM defect - one to many with mappedBy, updates can be made to fail

由 ☆樱花仙子☆ 提交于 2019-12-24 19:29:55
问题 Grails v3.3.9 - impacts live/dev and integration test My scenario is that I had an integration test that kept failing when building a manually created record and one found from DB, but works if you link two manually created records in the test. I have been trying a thousand tweaks and make sure GORM was doing what it said in docs. I've pared my code right back and built something simpler that looks structurally like my real stuff but is based on the Airport/Flights model in the GORM user

How to use mappedBy with more than one value JPA

由 别说谁变了你拦得住时间么 提交于 2019-12-12 02:53:17
问题 I have 2 tables: Currency and Rate The currency's primary key is referenced by the inputCurrency and outputCurrency foreigh keys in the Rate. How can I map these in order to cascadeALL? I tried in Rate (the table that contains the foreigh keys) @ManyToOne(cascade = CascadeType.ALL) @JoinColumn(name = "INPUT_CURRENCY") private Currency inputCurrency; @ManyToOne(cascade = CascadeType.ALL) @JoinColumn(name = "OUTPUT_CURRENCY") private Currency ouputCurrency; But if I delete an item from currency

Unidirectional one to many, and mapped by in Grails - can't get the integration test to pass

由 我的未来我决定 提交于 2019-12-11 17:45:08
问题 This has now been raised as a new query after all my explorations today which I believe is a defect - please read the newer post first. I have an RootEntity domain class and an EntityRelationship entity (I have separate explicit entity here as I want the relationship to have attributes of its own. I want two collections of unidirectional links from RootEntity to EntityRelationship like this A --references --> link (+attribs) --referenced by --> B Code: abstract class RootEntity { Long id

MappedBy in bi-directional @ManyToMany : what is the reason

由 生来就可爱ヽ(ⅴ＜●) 提交于 2019-12-06 02:39:12
问题 What is the reason for setting MappedBy in bidirectional many-to-many relationships? When one table has significant amount of records, while other has a few, which side is better to put mappedBy? 回答1: It's actually a good question, and it helps to understand the concept of an "owning" entity. If you want to prevent both sides (in a bidirectional relationship) from having join tables , a good idea, then you need to have a mappedBy= element on one side. Whether or not there is a join table is

MappedBy in bi-directional @ManyToMany : what is the reason

由 淺唱寂寞╮ 提交于 2019-12-04 06:42:27
What is the reason for setting MappedBy in bidirectional many-to-many relationships? When one table has significant amount of records, while other has a few, which side is better to put mappedBy? It's actually a good question, and it helps to understand the concept of an "owning" entity. If you want to prevent both sides (in a bidirectional relationship) from having join tables , a good idea, then you need to have a mappedBy= element on one side. Whether or not there is a join table is controlled by the mappedBy="name" element of the @ManyToMany annotation. The Javadoc for mappedBy for the
订阅 mappedby