•First
approach: Find
the most selective access
path, retrieve tuples using it, and apply any remaining terms
that don’t match the
index:
–Most selective access path: An
index or file scan that we estimate will require the fewest
page I/Os.
–Consider city=“seattle
AND phone<“543%” :
• A hash index on city can
be used; then, phone<“543%” must be checked for each retrieved tuple.
• Similarly, a b-tree index on phone could
be used; city=“seattle” must then be checked.