Question

I am writing a C++ program using OCI to call the stored procedure. In my PL/SQL stored procedure test, if not initializing an outbound variable, I might get “fetched column value is NULL” error because in case of foo != 0, bar is NULL. So in the first line, I initialize bar first. Is this the right way to handle outbound variable?

  FUNCTION function1(
    foo   IN  INTEGER,
    bar   OUT VARCHAR2
  ) RETURN INTEGER
  IS
    ret      INTEGER;
  BEGIN

    bar := ' '; -- do I need to initialize this variable?

    IF foo = 0 THEN
      ret := 0;
      bar := 'a';
    ELSE
      ret := 1;
    END IF;

    RETURN ret;

  END function1;

Answer 1

If you don’t set BAR in your program then the variable will be initialized to the default value of its type (NULL in this case, and for any type except for a record type with a non-NULL default value). That’s just basic logic.

So your choices are:

1. Accept the default value for the type of your variable.
2. Set BAR to the appropriate value in each branch of the IF statement.

Your posted code uses the first option. In the simple logic you present that is the approach I would take. If the internals were more complicated – an IF or a CASE with many branches – I would choose to have every branch explicitly set the value, because that would probably make the code’s intent clearer.