Spring Data : relationships between 2 different data sources

Question

In a Spring Boot Application project, I have 2 data sources:

• a MySQL database (aka "db1")
• a MongoDB database (aka "db2")

I'm using Spring Data JPA and Spring Data MongoDB, and it's working great... one at a time.

Saying db1 handles "Players", and db2 handles "Teams" (with a list of players' ID). Is it possible to make the relationship between those 2 heterogeneous entities working? (i.e. @ManyToOne, @Transactional, Lazy/Eager, etc.)

For example, I want to be able to write:

List<Player> fooPlayers = teamDao.findOneById(foo).getPlayers();

EDIT: If possible, I'd like to find a solution working with any spring data project

Answer 1

Unfortunately your conundrum has no solution in spring data.

what may be a possibility is that you create an interface (DAO) class of your own. That DAO class would have implementations to to query both of your DBs. A very crude and short example would be

your DAO
{
    yourFind (id)
    {
        this would find in db2 and return a relevant list of objects
        findOneByID(id)
        get the player from the above retrieved list and query db1
        getPlayer(player)
    }
}

i hope this points you in the right direction