How to get mapped entities from different databases?

Question

I have two different (entity1 and entity2) mapped (@OneToOne or @OneToMany) entities from two different database schemas (db1 and db2). If I try traditional ways, I got errors that are about "db1.entity2 does not exist". Because entity1 is in db1 and entity2 is in db2.

I tried to fill all the entity1 objects with entity2 objects after findAll();. But it takes a lot of time (more than 20 sec.)

Is there any way to map them to each other or fill after in a quick way?

Note: I can not get all the entity2 data from the database each time. Because there are a lot. Note 2: I will try to get entity2 objects I need, with Native Query by the list of id.

I use the last version of Spring Boot JPA Projection, MySQL db, and Java 11.

eastwater · Accepted Answer · 2020-10-20 05:42:17Z

0

You can add schema="db1" for entity1, and schema="db2" for entity2 in JPA annotation or xml mapping.

If there are a lot of entity2 for an entity1, declare the relationship as LAZY. You can use JPQL/Criteria API to get certain entity2(s) instead of native query.

Try Cmobilecom JPA that is small, fast and smart in generating SQL.

answered Oct 20, 2020 at 5:42

eastwater

5,80814 gold badges73 silver badges153 bronze badges

Sign up to request clarification or add additional context in comments.

1 Comment

menoktaokan Over a year ago

Actually, the problem is not that. I already configured the different databases with the schemas. I need something about business logic.

Collectives™ on Stack Overflow

How to get mapped entities from different databases?

1 Answer 1

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related