ESQL2: an object-oriented SQL with F-Logic semantics

ESQL2 is an SQL2 upward-compatible database language that integrates the essential concepts of relational, object-oriented, and deductive databases. ESQL2´s salient features are a rich and extendible type system based on abstract data types (ADTs) implemented in various programming languages, complex objects with object sharing by combining generic ADTs and object identity, the capability of querying and updating relations containing simple or complex objects using SQL-compatible syntax and semantics, and a DATALOG-like deductive capability provided as an extension of the SQL view mechanism. A declarative semantics is proposed for ESQL2 retrieval statements using F-Logic, which provides a solid basis for understanding the integration of objects and relations