Please explain how to connect two entities in different bundles on symfony2?

Question

symfony

This question has already been asked, but I can't figure out how to implement it.
They gave me a reference:
Link
Still, nothing is clear.
Explain on the fingers, if not difficult.

Answer 1

To begin with, let me clarify, do you want to link entities from different bundles or do you want to specify an abstract class or interface as a link?
In general, what you have given asks you to specify as a link (targetEntity) an interface or an abstract class with which you want to connect an entity, and in the config, specify the mapping, which interface corresponds to which implementation.