Performance: If...Then...Else vs Decode

I want to decode the value of a column within an Insert Trigger to provide a description.

Setting aside any data redundancy issues...

If I want to use Decode, I have to do something like this...

        select Decode(:new.MyCode, 'C', 'Cat',
                                   'D', 'Dog',
                                   'P', Parrot',
                                   'E', 'Elephant', NULL)
        into :new.MyDescription
        from Dual;

Not only does this mean that I am making a function call, but also issuing a DML statement.

How inefficient is this, bearing mind that the code will be called many times, in comparison to the more verbose method of...

        if :new.MyCode = 'C' then


                :new.MyDescription := 'Cat';


        else if :new.MyCode = 'D' then


                :new.MyDescription := 'Dog';


        ...
        else


                :new.MyDescription := NULL;


        end if;

--
Alan Received on Wed Dec 23 1998 - 13:30:47 CST