Translating GraphLog to SQL
Frank Ch. Eigler · Conference of the Centre for Advanced Studies on Collaborative Research · 1994
The Hy+ database visualization system uses GraphLog, a novel graphical language to express a wide range of queries that have been traditionally outside the reach of relational languages. Therefore Hy+ has used various deductive database systems (Prolog, LDL*, CORAL*) to compute GraphLog queries.With large or legacy databases, however, it is desirable to use relational databases like IBM* DB2* for AIX* to perform the computations involved in answering a GraphLog query, largely because such mature relational systems are heavily optimized, widely available, and natively support a client-server style.The forthcoming Version 2 of DB2 for AIX will include features that allow a translation of a large class of GraphLog queries into a list of extended-SQL statements that can be efficiently executed by the database engine. Using this version of DB2 for AIX as a back-end allows Hy+ users to compute complex queries against large databases. We describe certain technical aspects of the GraphLog language and detail the GraphLog-to-SQL translation algorithm.