next up previous
Next: Projection Operation Up: Equivalence of Expressions Previous: Equivalence of Expressions

Selection Operation

  1. Consider the query to find the assets and branch-names of all banks who have depositors living in Port Chester. In relational algebra, this is

    (customer  tex2html_wrap_inline828  deposit  tex2html_wrap_inline828  branch))

  2. Suggested Rule for Optimization:
  3. Second Transformational Rule:

Osmar Zaiane
Sun Jul 26 17:45:14 PDT 1998