![]() ![]() It doesn’t define when the primary key value has to be assigned. You don’t find any information about this in the JPA specification.Persist the given transient instance, first assigning a generated identifier. The Javadoc of Hibernate’s save method states that it generates the primary key value first:.That might seem like a huge difference, especially when you take a closer look at Hibernate’s Javadoc and the JPA specification: JPA’s persist method returns void and Hibernate’s save method returns the primary key of the entity. Return Types And Execution Of SQL StatementsĪnother obvious difference between these 2 methods is their return type. It is, therefore, not available in other JPA implementations.īut that’s only relevant if you want to be able to replace Hibernate with another JPA implementation, like Eclipse Link or OpenJPA. The save method, on the other hand, is Hibernate-specific. You can use it with all JPA implementations. The most obvious difference is that the JPA specification defines the persist method. Both methods seem to do the same, but there are a few differences. You can either use JPA’s persist or Hibernate’s save method to do that. You need to attach the entity to a persistence context so that it becomes managed and gets persisted in the database. When you create a new entity object, it’s in the transient lifecycle state. Persisting A New Entity Using persist Or save You can schedule an entity for removal by calling the remove method on the EntityManager interface. Removing entities is outside of the scope of this post, so I will not get into too many details about it. ![]() These entities were previously in the state managed, before you scheduled them for removal. JAVA MERGE METHOD MAP UPDATEI will get into more details about how you can reattach these entities with JPA’s merge and Hibernate’s update methods in a later part of this post.Īnd the last lifecycle state is removed. That can be the case because you closed the persistence context or you explicitly detached the entity from the current context. As long as an entity is in the transient state, it is not mapped to a database record and not managed by any persistence context.Įntities in the detached lifecycle state are no longer managed by the persistence context. I will show you how you can do that with JPA’s persist and Hibernate’s save method, in the following section. It remains in this state until you attach it to the current persistence context. When you create a new entity, it’s in the transient state. ![]() A managed entity is also stored in the 1st level cache. Your persistence provider generates the required SQL INSERT and UPDATE statements to propagate all changes. That means that it is mapped to a database record. If an entity is attached to the current persistence context, it has the lifecycle state managed. ![]()
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