About merge

manual

Detached Entity Objects

Explains detached entity objects and how to work with detached objects in JPA, including merging them into an EntityManager.... Detach Bulk Detach Explicit Merge Cascading Merge Explicit Detach When a managed entity ...

 
forum_thread

Problem on JPA Merge Entity.

Hello, I have a problem with the EntityManager.merge() function. I set a property value of an entity (statement) with an other entity (newSingleConstraint). newSingleValue is already persisted. I do this myself (no use of cascade because sometimes the newSingleValue is already in database).   The statement update don't throw exception. And when i try to reload statement the value i have set before is a null value. I check with the Explorer, the statement has a null value on the property and the newSingleValue is present.... Hello, I have a problem with the EntityManager.merge() function. I set a property value of an entity (statement) with ... throws DaoException { entityManager. merge ( ergoClass ) ; } } ...

 
forum_thread

Extra uninitialised entities spawned on merge()

In the following, Element is a base entity class, with a bi-directional @ManyToOne-@OneToMany relationship Element owner - List<Element> ownedElements, and Example is a subclass entity with a relationship @OneToOne Element child. ... final static boolean DO_PERSIST_BEFORE_MERGE = true ;   /** * @param args the command line ... ;   if ( DO_PERSIST_BEFORE_MERGE ) { em. getTransaction ( ) . ...

 
api-jpa

merge(entity)

Merge the state of the given entity into the current persistence context.(Method of javax.persistence.EntityManager)

 
forum_thread

NullpointerException when execute a merge

How can we analyze the cause of an "Unexpected internal exception"?   We create an object tree that is persisted with "merge()". Then we want to persist “merge()” an new object of a different type.   [we use ObjectDb 2.6.0_3] ... We create an object tree that is persisted with "merge()". Then we want to persist “merge()” an new object of a different type.   [we ...

 
forum_thread

Selective merge/cascade of detatched entity

I'm having an issue with my application, and I'm hoping you guys will be able to help. Please forgive typos and obvious errors, I'm having to retype from a non-internet connected network. A contrived example is: ... many numerical targets for the new company. I then need to merge each salesman back into the database to keep it in step. The code i have ... for ( Salesman s : salesmen ) em. merge ( s ) ; This appears to have the effect of ...

 
manual

Advanced JPA Topics

Describes advanced JPA topics - detached entity objects, lock management and entity lifecycle events. This section discusses advanced JPA topics: Detached Entity Objects Locking in JPA JPA Lifecycle Events Shared (L2) Entity Cache JPA Metamodel API ...

 
api-jpa

CascadeType.MERGE

Cascade merge operation(Enum Constant of javax.persistence.CascadeType)

 
forum_thread

Merge Issue: Attempt to reuse an existing primary key value

Hello, I have just updated my objectdb version from 2.4.6 to 2.5.5. I observed a new bug or a feature on an ordinary merge operation. This is the test case ( work in 2.4.6 version ) : 2 parents object share the same child on a ManyToMany relationship with Cascade.ALL constraint. ... I observed a new bug or a feature on an ordinary merge operation. This is the test case ( work in 2.4.6 version ) : ... em = null ;   // Merge parent1 em = emf. createEntityManager ( ) ...

 
forum_thread

Merge on detached entities

Hello, it is possible to merge detached entities? There are some attached entities which load from the database. The transaction is finished and the entities become detached. In a new transaction the fields of the detached entities will be changed and a merge by em.merge(entity) will be saved the entities. Can this works correctly? How are the rules of the merge process? Do the changed fields of the detached entity overwrite the fields in the database? Also changed fields which are set to null? ... Hello, it is possible to merge detached entities? There are some attached entities which load ... the fields of the detached entities will be changed and a merge by em.merge(entity) will be saved the entities. Can this works ...