Abstract: A system for mapping, converting, pruning, flattening, and persisting data amongst object-oriented systems and relational systems. Object class definitions and JSON objects define an object-oriented system and a relational database defines a relational system. An Object Relational Mapping (ORM) system exchanges data between an object-oriented system and a relational system. An ORM system includes an ORM Grammar, an ORM Specification, an ORM Data Structure, and an OR Mapping Unit. Data transfer can be achieved amongst relational and non-relational systems. An Object Conversion System (OCS) system exchanges data between one or more object-oriented systems. An OCS system includes an OCS Grammar, an OCS Specification, an OCS Data Structure, and an Object Conversion Unit. The ORM and OCS Specifications may use virtual attributes including path expressions. A path expression includes a chain of attribute names to specify a nested attribute in an object graph.

Abstract: A system for exchanging data and commands between an object oriented system and a relational system. The system includes an Object-Relational Mapping (ORM) grammar, an ORM specification, Object Class Definitions, a relational database, an operating system, a Database Exchange Unit including an OR mapping unit, a schema generator, a schema reverse engineering unit and applications. The ORM specification is based on the ORM grammar and includes information for defining the mapping between object-oriented system and the relational system. The Object Class Definitions define the object-oriented system, and the relational database defines the relational system. The Database Exchange Unit executes in accordance with the ORM specification, and is the programs/routines that operate to translate data from the object model to the relational model, and vice versa.