Working with OR condition lists

Calling dam_getSetOfConditionListsEx with the UNION option causes a portion or all of the WHERE clause to be returned as a set of condition lists combined as OR expressions. Each condition list contains one or more conditions combined as AND expressions.

You can navigate through the condition list by calling dam_getFirstConditionList and dam_getNextConditionList.

You can then navigate each condition list using dam_getFirstCond and dam_getNextCond.

Since each of these conditions may be on different columns, use dam_getColInCond to find the column on which the condition is specified. The format of the UNION set of condition lists is:

(cond1 AND cond2 AND...) OR (cond3 AND cond4 AND...) OR...

Example 1

SELECT * FROM parts

WHERE (partno=10 AND supplier = S1) OR (partno = 20 AND supplier = S2)

Requesting conditions on all columns returns the condition lists:

R1 = (partno=10 AND supplier = S1)

R2 = (partno = 20 AND supplier = S2)

This is interpreted as R1 OR R2.

Example 2

SELECT * FROM restaurant_map

WHERE (food = 'Thai' AND location = 'San Jose') OR (food = 'Indian' AND location = 'San Francisco' AND wine_selection IS NOT NULL) OR (food = 'Chinese' AND location = 'San Jose')

Requesting conditions on all columns returns the condition lists:

R1 = (food = 'Thai' AND location = 'San Jose')

R2 = (food = 'Indian' AND location = 'San Francisco' AND wine_selection IS NOT NULL)

R3 = (food = 'Chinese' AND location = 'San Jose')

This is interpreted as R1 OR R2 OR R3.