Summary form only given. ROL (Rule-based Object Language) is a deductive object-oriented database system. It provides a uniform language for defining, querying and manipulating a database. The ROL language integrates important features of deductive databases and object-oriented databases with well-defined declarative semantics. ROL also supports structured values, treating them as first-class citizens, and providing powerful mechanisms for representing both partial and complete information about sets. As a result, it directly supports non-first normal form relations and is an extension of pure value-oriented deductive database languages. A ROL database consists of three parts: a schema, a set of facts and a set of rules. The ROL system is organized into three layers: (1) the user interface (textual and graphical); (2) the query manager and the update manager; and (3) the memory manager and the object manager.