The Integration Service processes an uncached lookup the same way it processes a cached lookup except that it queries the lookup source instead of building and querying the lookup cache.

When the lookup condition is true, the Integration Service returns the values from the lookup source. When the Integration Service processes a connected Lookup transformation, it returns the values represented by the lookup/output ports. When it processes an unconnected Lookup transformation, the Integration Service returns the value represented by the return port.

When the condition is not true, the Integration Service returns either NULL or default values. When the Integration Service processes a connected Lookup transformation, it returns the default value of the output port when the condition is not met. When it processes an unconnected Lookup transformation, the Integration Service returns NULL when the condition is not met.