(Object-Relational Mapping) Converting data from tables in a relational database to objects and vice versa. Many applications employ object-oriented programming, but keep the data in traditional relational tables. The O-R mapping function can be accomplished with statements in the object-oriented programming language or via a third-party O-R mapping program. For Complex Relationships When an object model is very complex with a large number of many-to-many relationships, it takes time to store the data in relational tables. This "impedance mismatch" is resolved with the use of an object database, which is designed for complex object data. See object database and object-oriented programming.