You were getting the error because there is no such Destroy() method for
the SQLListTables class.
The only two classes that have the Destroy() method are: SQLStatement
and SqlParameter classes. Unrelated, but just in case you use
SQLParameter, according to the SDK, "If you instantiate a SQLParameter
object, you should explicitly destroy it when you are finished using it".
And remember the Close() method only closes the cursor, not the connection.
As you found, the Close() method should work fine.