Query processing in DOQL: A deductive database language for the ODMG model

This paper describes the architecture, algebraic query processing framework and query execution approach that comprise the implementation of the deductive object query language (DOQL) query processing system. To the best of our knowledge, it is the first deductive object query language to be designed and implemented as a complementary and non-intrusive query component within an ODMG OODBMS architecture. The query processing framework enables the combined use of logical rewriting and algebraic optimization, and features an object algebra, local and global query optimization, physical execution algorithms implemented as iterators, and a query execution engine implemented using the dataflow technique. Several representative DOQL queries are also provided, illustrating the flexibility and expressiveness of querying object databases with DOQL.