When to Use the Query Protocol
Use the query protocol if:
•The component method is called in an invocative constraint that must check if a rule is violated.
You want the component method return a value that will be interpreted by the Rules Engine as "record returned", "no record returned" or "error". Specify a query protocol association with the method as its Execute Method. Do not specify a Fetch Method.
•You want the component to return more than one 'record' for each record it gets fed. Specify a Query Protocol Association with both an Execute Method and a Fetch Method.
NOTE: If you want the end user to perform an external action simply by pushing a button, use the standard protocol instead of the query protocol.