How to query in Database Relationship

The user is having trouble querying relationships in a database. The current database does not support querying relationships. They have a collection called "ServiceFavorite" that stores favorites of different users and they want to use a query to only get documents owned by the current user. They are wondering if the related items should appear in the results if they fetch the user profile. They also mention that the "ServiceFavorite" collection has attributes "service" (related to the service collection) and "user" (related to the userProfile collection). They ask how they can query to get the favorites of the current user. Unfortunately, no solution is provided in the support