To optimize query performance, the DBMS Server often inverts the sense of a comparison operation. To make this possible, you must define a complementary function instance for every function instance of fid_optype II_COMPARISON that you define.

For example, if you define a function instance for the equals (=) operator, you must also define a function instance for its complement, not equals (!=). Note that the complement of “>=” is “<“, and the complement of “<=” is “>".

Complementing function instance definitions must agree. That is, if A is a function instance whose complement is B (A's fid_cmplmnt = B's fid_opid), the complement of B must be A (B's fid_cmplmnt = A's fid_opid).