About ManyToMany

forum_thread

Persist error @ManyToMany how to define correct entities relationships

I have Product entities containing a list of Category enties. Each product can have multiple Category but all sue the same limited set of Category entities. There is not changes made to Category from Product. The category ID is taken from the webservice Object ID (unique too). ... private long id ;   @ ManyToMany ( cascade = CascadeType . PERSIST ) ... . Id ; import javax. persistence . ManyToMany ; import javax. persistence . Persistence ; ...

 
api-jpa

javax.persistence.ManyToMany

Defines a many-valued association with many-to-many multiplicity.(Annotation of JPA)

 
manual

JPA Entity Fields

Explains how to define and use primary keys in JPA, including composite and embedded primary keys.... See JavaDoc Reference Page... , ManyToMany javax.persistence.ManyToMany JPA annotation Defines a many-valued association with ...

 
api-jpa

JPA Annotations for Relationships

Reference (JavaDoc) of JPA 2 relationship annotations, including @ManyToMany, @ManyToOne, @OneToMany, @OneToOne, @OrderBy and @MapKey.... the following annotations: javax.persistence.ManyToMany javax.persistence.ManyToOne ...

 
forum_thread

Find the error...JPA ENTITY HIBERNATE

Hey guys....i am searching for some days for the problem...Maybe one of you can find the error   DATABASE SHEMA: https://www.file-upload.net/download-12530779/2017-06-0214_25_00-MySQLWorkbench.png.html       Entities:   ... JoinTable ; import javax. persistence . ManyToMany ; import javax. persistence . ManyToOne ; ... ) private String email ;   @ ManyToMany @ JoinTable ( name = "chat" , ...

 
forum_thread

How to Remove records from many to many relationship tables in JPA

Hello All, I am getting the constraint violation exception whil deleting the entries I have Relation tables    TransportationEvent  and Conclusion  , relations like ... class TransportationEvent { ... @ ManyToMany ( fetch = FetchType . EAGER , cascade ... public class Conclusion { .... @ ManyToMany ( fetch = FetchType . LAZY , cascade ...

 
forum_thread

EntityManager.refresh takes a long time

EntityManager.refresh takes a long time for entity object Person in this code: ... ( ) ;   @ ManyToMany ( cascade = CascadeType . REFRESH ) ... ( ) ;   @ ManyToMany ( mappedBy = "selectedPersons" , cascade ... DialogAction currentDialogAction ;   @ ManyToMany ( fetch = FetchType . EAGER , cascade ...

 
forum_thread

Left join fetch behaviour doesn't retrieve children?

Hello support, I'm a little bit confused about a left join fetch behaviour. In this test case, i try to fetch my 3 children using a left join fetch. But my collection is null after closing the em. It was expected to be fetched before closing the em, no ? In fact, that is the objective of the fetch purpose (i guess ?). ... . Id ; import javax. persistence . ManyToMany ; import javax. persistence . Persistence ; ... ) ; }   @ ManyToMany ( targetEntity = MyEntityChild. class , ...

 
forum_thread

Removing objects where ManyToMany relationships exist

Consider you have an entity Entity with the following unidirectional relationship: @ManyToMany private Set<OtherEntity> setOfOtherEntities; public Set<OtherEntity> getOtherEntities() {     if (setOfOtherEntities == null) {       setOfOtherEntities = new TreeSet<OtherEntity>();     }     return setOfOtherEntities;   } ... with the following unidirectional relationship: @ManyToMany private Set<OtherEntity> setOfOtherEntities; ...

 
forum_thread

Cascading persistence through an inverse field

Hi! I was playing with cascading persistence with @ManyToMany and inverse @ManyToMany fields, and I noticed that I can only get cascading persistence in one direction. If the "owner" of the relationship is persistent, then objects that are added to the relationship are automatically made persistent. However, I can not get this to work the other way around. I would also like the relationship owner to be persisted if a persisted object is added on the owner side. I have included a minimal example: ... I was playing with cascading persistence with @ManyToMany and inverse @ManyToMany fields, and I noticed that I can only get cascading persistence in ...