APRIL. Another PRODAT implementation

This report APRIL, which is a prototype implementation of the non-standard database system PRODAT developed in the PROSYT project. The PRODAT object model is a derivative of the Entity-Relationship Model with a special focus on complex objects. It provides attributed objects with longfields and a structuring mechanism to build arbitrary acyclic object graphs. Further PRODAT concepts implemented in APRIL are versions, a transaction concept taylored to the data model, and an integrated archiving component. Some other parts defined in PRODAT are emitted in APRIL, among others because it is directed to graphics applications and their data handling. In APRIL, interfaces are offered on three different levels: There is a procedural C interface which covers the whole functionality, two alphanumeric interpeters (e.g. for batch jobs), and a graphical interactive database editor, the so-called object editor.