CODEWITHSUNDEEP
javaspringhibernatespring-bootjpa
user1234SI.
user1234SI.

Reputation: 1860

How can I write jpa repository method for m:m relationship?

I have a m:m relationship between EntityOne and EntityTwo

public class EntityTwo{
     private String name;
     @ManyToMany //config here
     private List<EntityOne> entities;
}

public class EntityOne{
     private String description;
     @ManyToMany //config here
     private List<EntityTwo> entities;
}

How can I create a method for EntityOne repository without using the @Query annotation for fetching all the EntityOne rows based on EntityTwo's name ? I've tried something like :

List<EntityOne> findAllByEntityTwoName(String name) but it doesn't work.

Upvotes: 1

Views: 428

Answers (2)

Shababb Karim
Shababb Karim

Reputation: 3703

You can use Spring data query methods to achieve your task. Basically, spring data generates a query based on some rules you define your method with.

@Repository
public interface EntityRepository extends JpaRepository<EntityOne, UUID> {

    List<EntityOne> findAllByEntities_Name(String name);
}

In the findAllByEntities_Name() method, you are using query method along with Property Expressions to create a search by name property in entites(EntityTwo) field from EntityOne

Upvotes: 1

vishnu
vishnu

Reputation: 2011

Let's say you need to query EntityOne based on the field name in EntityTwo.

You can create a method like this: findAllBy + Name of EntityTwo defined in EntityOne + EntityTwo attribute names, based on which you need to filter

So in you case it would be

List<EntityOne> findAllByEntitiesName(String name);

Upvotes: 1

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