DB Design Tute 4 Procedural languages state what data is required rather than how to retreive the data. SQL is non-procedural. 5 basic relational algebra operators: selection (unary - requires 1 input), projection (columns), union, intersection & cartesian product. Todd Emilliom@optusnet.com.au 6290 0709 h 0412 085 690 m 6240 5807 w Twu 0422 231 788 m twu_kark@hotmail.com Peter Peter.snowdon@customs.gov.au 0403 815 380 (m) 6275 5967 w 6251 2540 h