[FIXED] Fill JPA fill child array (one to many) with only certain children

Issue

I need to fill a Entity with the children entities and it works well when I need all children but now I only want to have a few ones.

For example, I have Owner 1-----n Pet

If I ownerRepositoty.findAll(); I get all owners with each one having an array of all he's pets. But let's say I want to get all the owners with the pet array having only the ones which name starts with N.

Example of the parent entity:

public class Owner {
    @OneToMany(mappedBy="Owner")
    private Set<Pet> pets; //This gets filled with all pets

    //getters & setters
}

And the child entity:

 public class Pet {
        @ManyToOne
        @JoinColumn(name="owner_id", nullable=false)
        private Owner owner;

        //getters & setters
 }

I tried with a JOIN FETCH as explained here in the repository query but It just made a normal sql JOIN which is not what I'm looking for.

Any ideas?

Solution

I found the way to do this: You can use the @Where annotation to filter the childs of a one to many or a many to many relationship.

public class Owner {

    @OneToMany(mappedBy="Owner")
    @Where(clause = "name like 'N%'")
    private Set<Pet> pets; //This gets filled with pets with a name starting with N

    //getters & setters
}

Answered By - Carlos López Marí
Answer Checked By - Candace Johnson (JavaFixing Volunteer)