Semantic Query Optimisation and Rule Graphs.
Jerome Robinson, Barry G. T. Lowden · 1998
Previous researchers note the problem for semantic optimisation of database queries caused by its production of a large number of semantically equivalent alternative queries, tom which one must be quickly chosen. The present paper observes that this is caused by the nontmiform structure of rules, which also (i) prevents fast access to rules, (ii) allows the rule base to become impractically large, and (iii) such rules anyway are of low utility for SQO. Simple rules are less expressive but more useful in this application. Single-antecedent, single-consequent rules are the main component of the rule base. The rule set