16. The method of claim 1 , wherein said optimizing step includes substeps of: placing a candidate plan segment in a next position in an access plan being constructed, the candidate plan segment comprising a plan node, access method and join method valid at the next position; and evaluating the access plan including the candidate plan segment.
16. The method of claim 1 , wherein said optimizing step includes substeps of: placing a candidate plan segment in a next position in an access plan being constructed, the candidate plan segment comprising a plan node, access method and join method valid at the next position; and evaluating the access plan including the candidate plan segment. 20. The method of claim 16 , wherein said optimizing step further comprises substeps of: if the access plan is more favorable than an access plan previously identified and is a complete plan, considering alternative access plans by repeating the placing and evaluating substeps until reaching a pre-selected limitation on consideration of alternative access plans.