CODEWITHSUNDEEP
javaspringhibernaterestjpa
onlydmc123
onlydmc123

Reputation: 83

How to properly update entities using REST and JPA/Hibernate

I have entity Document, which has lots of columns, one-to-one, one-to-many and many-to-many mappings to some other entities.

Example:

Document:
  id,
  title,
  body,
  authors,
  viewers,
  ...

Using REST, I want to update some particular document, controller receives serialized Document object, calling EntityManager's merge method persists null results to the database if controller received for instance only body , then I want the body to be updated only, but merge deletes records for title, authors and viewers and etc.

I understand that it is a standard behavior of EntityManager, but I am asking what is the most preferred technique to do updates on entities without receiving whole entity from front-end or some other endpoint. Should I load the entity from database using the id I received and set MANUALLY all of the fields and then save to database or should I use another technique.

I don't have any problem with writing manually all of the setters to copy the changes, but entities are really big in size with lots of relations. Asking for best practice in this case.

I know about DTOs but I want alternate approach when using entities for controllers and service methods.

Upvotes: 1

Views: 2530

Answers (2)

ajay tomar
ajay tomar

Reputation: 382

There are two options one is update query, which works fine but you may feel you are loosing some hibernate features and simplicity of the code. Else you can do it in Hibernate way like below

   AuditorBean auditorBean = (AuditorBean) session.get(AuditorBean.class, AuditorBean.getId());
    auditorBean.setFirstName("aa");
    auditorBean.setLatName("bb");
    auditorBean.setTrainLevel("ISO");
    auditorBean.setAccessLevel(4);

Here you should not call any method like saveOrUpdate() or merge(). object is attached with transaction, so object is flushed and committed at the end of the transaction automatically .

Upvotes: 1

osama yaccoub
osama yaccoub

Reputation: 1866

For entity partial update, you will need to use either criteria api or jpql ... if you are using older versions with no criteria update or old query parser where jpql update is not allowed you will have to read from database first, update then insert again .... you can also make use of updatable=false for columns that should be only set on creation (like CREATION_DATE) and there is also a nice feature in hibernate called @DynamicUpdate which I haven't tried but looks brilliant ... It only updates the modified field (check Vlad's post here) ... concerning the DTO DP , I you might always need to use if you want to hide / modify some data from the client regardless to the way you store the data ... and it's always a good way to separate concerns (but comes with the mapping headache between domain & DTO objects which is much released thanks to spring converters)

Upvotes: 3

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