Start Entitymanager merge not updating

Entitymanager merge not updating

Now Entity B would be managed by Entity Manager Y due to the cascading behavior you cited. And I come to the conclusion, that the only way to interpret it, is that managed entities of the SAME persistence context are meant. The spec also spelled out the following; ================================= 3.2.8 Managed Instances It is the responsibility of the application to insure that an instance is managed in only a single persistence context.

==================== merge() is for "detached" entity only. Per Spec: ==================== 3.2.7.1 Merging Detached Entity State The merge operation allows for the propagation of state from detached entities onto persistent entities managed by the entity manager. If an entity is managed by the SAME persistence context, there is nothing to merge since the state of X is already maintained, hence the merge operation is ignored.

The semantics of the merge operation applied to an entity X are as follows: ........ And I come to the conclusion, that the only way to interpret it, is that managed entities of the SAME persistence context are meant. However, the child relationship is still processed if proper cascade is specified.

I do very much wish that Top Link would have much better support for GUI based tools, especially administrative tools.

figures out how to persist the domain by looking at the ORM configuration, it performs the CRUD (create, read, update and delete) operations on the domain objects in this section you will learn about the starts to manage an entity, it synchronizes the entities state with the database, it also ensures that any changes are reflected in the database, it accomplishes this by holding an object reference to the managed entity and periodically checking for data freshness, if it finds that the entity has changed it synchronizes with the database.

When the can no longer reach the entity it is said to be detached ( it can be moved out of scope by either being removed, serialized or cloned), an entity will also be detached immediately when no transaction is associated with it.

An entity becomes attached when you use does the opposite.

Before call Entity Manager.merge() method, I uses entity Manager.contains() method to ensure the Child Entities are managed. but when I call Entity Manager.merge(team) to update the parent entity, hibernate generated the "insert" SQL to update child entity and display "unique constraint" ...

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You can detach an entity to upload it to the web tier, the web tier can then update it and then send it back, we then reattach it and it updates the database.

The persistence context plays a vital role in the internal functionality of the If a persistence context is under transaction scope, entities attached during a transaction are automatically detached when the transaction ends.

So be careful not to rely on when the statement gets executed, but you can be sure that it will executed before the transaction completes.