An extended recursive algebra for nested relations and its optimization
B. Rathakrishnan, J.L. Kim · 2002
This paper considers query optimization for nested relational databases based on a recursive algebra. A recursive algebra which has been proposed in the literature for nested relations has been extended to accommodate arbitrary algebraic expressions in any nested level of the query. This extended algebra can be used to conveniently express queries in two query languages proposed for the nested relational model. A semijoin based algebraic optimization strategy for queries expressible in this algebra is described, which is a recursive extension of an 1NF optimization technique with some modifications.>