An unconnected SQL transformation is an SQL transformation that is not connected to the mapping pipeline. Use an unconnected SQL transformation to call a stored procedure.
You use an Expression transformation to call the unconnected SQL transformation with an :SP expression. Or, you configure the SQL transformation to invoke a stored procedure before or after a mapping run. For example, you might use an unconnected SQL transformation to remove temporary source tables after the mapping receives data from the source.
You might also use an unconnected SQL transformation when you want to call a stored procedure multiple times in a mapping.