1. A method for retrieving target objects stored in a relational database to which an object model is mapped, the method comprising steps of: generating a retrieval query to read target objects for a collection of source objects, the collection of source objects having many-to-many relationships with the target objects, the collection of source objects and target objects being respectively stored in one or more source tables and target tables in the database, and the many-to-many relationship being defined in the database by using an intermediate join table of the source tables and the target tables; selecting join table information from the many-to-many join table relating to the collection of source objects and the target objects to enable matching of the target objects and the source objects using the join table information; and retrieving the matched target objects by executing the retrieval query on the database.