More semantic analysis - and objections - in 28 April quiz (2244)

This quiz asked: "Which of these choices describe a way in which a value can be assigned to a PL/SQL variable?"

We scored as correct the following: "Change the value of a variable by passing it as an argument to a procedure or function." Why? Because you can define an OUT or IN OUT parameter and then change the value of the variable passed as an actual argument to that parameter within the body of either a procedure or function.

Several players wrote with objections like these:

"The variable is not actually changed by the act of passing it as a parameter to a procedure or function. It is actually being modified by the assignment that happens in the body of the procedure or function. I believe that your test code for that option is actually just another example of the first option (Assign a value to a variable using the assignment syntax)."


"A variable can be assigned by passing it as a parameter to a procedure, but it cannot be assigned by passing it as a parameter to a function, so it is ambiguous whether the last option should or should not be selected."


My responses:

First, you can define OUT and IN OUT parameters in a function's parameter list, so "procedure or function" in the question does not affect the correctness of the answer. Having said that, I recommend, as do many others, that you do not include OUT and IN OUT parameters in a function's parameter list. It restricts how you can use the function (cannot call it in an SQL statement, for example), but I also believe that your functions are easier to understand, use and maintain they it only passes data back through the RETURN clause.

Second, regarding the issue of whether and when the value of a variable passed as an argument is changed: the question asked "can be assigned" [my emphasis]. The word "can" means that, and I believe is fairly commonly interpreted as, "it is possible". It does not mean that every time you pass a variable as an argument it will be changed. It does not ask you to specify the mechanism by which the change takes place.

As I read over this post, I realize that it is likely that a number of players objected because they analyzed the correctness of the choice "Change the value of a variable by passing it as an argument to a procedure or function." independently of the question. If I asked you to answer true or false to "The value of a variable is changed by passing it as an argument to a procedure." I could see why you might say "It depends."

Remember, though, that you must evaluate each choice as an answer to the question, not as an independent statement. When this is done, the "can" of the question establishes that you must only determine if such a thing can (is possible) happen.