A computer software system is provided, namely an Object Process Graph Relational Database Interface (OPGRDI) system. The OPGRDI defines and updates relational database tables based on an OPG and stores and retrieves data in the tables as an OPG-defined application is run. The OPGRDI also defines and updates OPG persistent data object elements based on relational database table schemas. The OPGRDI functions can be enabled by users who want to store and retrieve application information in a relational database system, such as Oracle, Sybase, SQL Server, etc. The OPGRDI alters relational database tables as a user changes the structure of an OPG-defined application.