フリー問題

問題文

A cleanup script calls the drop procedure for a graph that may not be there. How can it avoid raising an error?

選択肢

1. Pass the name as a list, which is silently ignored when the graph is absent from the catalog at the time of the call.
2. Pass the second parameter as false, which makes the procedure return an empty result instead of raising an error for a graph that does not exist.
3. Set the database name parameter to an empty string, which makes the procedure treat a missing graph as a success.
4. Call the list procedure first, because the drop procedure has no way of tolerating a missing graph and will always raise an error when the name cannot be found.