What is the best way to update the entity in JPA

Question

I am doing some CRUD operations using JPA  For updating an object which is the right way to do    Through update query or through the find method of EntityManager  I have one Employee object I need to update  Which is the right way    Please guide me

User · Answer

That depends on what you want to do  but as you said  getting an entity reference using find   and then just updating that entity is the easiest way to do that    I d not bother about performance differences of the various methods unless you have strong indications that this really matters

User · Answer

It depends on number of entities which are going to be updated  if you have large number of entities using JPA Query Update statement is better as you dont have to load all the entities from database  if you are going to update just one entity then using find and update is fine

User · Answer

Using executeUpdate   on the Query API is faster because it bypasses the persistent context  However    by-passing persistent context  would cause  the state of instance in the memory  and the actual values of that record in the DB are not synchronized   Consider the following example     Employee employee   Employee entityManager find Employee class   1    entityManager       createQuery  update Employee set name     xxxx   where id 1         executeUpdate      After flushing  the  name in the DB is updated to the new value but the employee instance in the memory still keeps the original value  You have to call  entityManager refresh employee  to reload the updated name from the DB to the employee instance It  sounds strange  if your codes still have to manipulate the employee instance after flushing but you forget to refresh   the employee instance as the employee instance still contains the original values   Normally   executeUpdate   is used in the bulk update process as it is faster due to bypassing the persistent context  The right way to update an entity  is that you just set the properties you want to updated through the setters and let the JPA to generate the update SQL for you during flushing instead of writing it manually       Employee employee   Employee entityManager find Employee class  1      employee setName  Updated Name

[java] What is the best way to update the entity in JPA

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