9. The method of claim 1 , further comprising representing the predicate expression with an operator-based parse tree structure if the indicator has a first value, and representing the predicate expression with a function-based parse tree structure if the indicator has a second value, the operator-based parse tree structure and function-based parse tree structure being two of the plural types of data structures.
9. The method of claim 1 , further comprising representing the predicate expression with an operator-based parse tree structure if the indicator has a first value, and representing the predicate expression with a function-based parse tree structure if the indicator has a second value, the operator-based parse tree structure and function-based parse tree structure being two of the plural types of data structures. 11. The method of claim 9 , further comprising receiving a statement to set the value of the indicator for the user-defined routine.