Retrieve Hibernate associated entity with pagination

Question

I am stuck with an issue. I have 3 tables that are associated with a table in one to many relationship.

• An employee may have one or more degrees.
• An employee may have one or more departments in past
• An employee may have one or more Jobs

I am trying to fetch results using named query in a way that I fetch all the results from Degree table and Department table, but only 5 results from Jobs table. Because I want to apply pagination on Jobs table.

But, all these entities are in User tables as a set. Secondly, I don't want to change mapping file because of other usages of same files and due to some architectural restrictions.

Else in case of mapping I could use BatchSize annotation in mapping file, which I am not willing to do.

Answer 1

The best approach is to write three queries:

1. userRepository.getDegrees(userId);
2. userRepository.getDepartments(userId);
3. userRepository.getJobs(userId, pageIndex);

Spring Data is very useful for pagination, as well as simplifying your data access code.

Hibernate cannot fetch multiple Lists in a single query, and even for Sets, you don't want to run a Cartesian Product. So use queries instead of a single JPQL query.