I published yet another PL/SQL puzzle on Twitter yesterday. Generated lots of interest and interesting replies. I don't think any single person caught everything, but as usual the community came through.
I will repeat the puzzle here. If you haven't already seen it on Twitter, please try to solve it yourself before looking at my answer.
White space
so you do not immediately
see my answers.
:-)
OK, let's dive in.
Notice, first of all, that I asked about text that can be removed, not lines. So you can remove entire lines or portions of lines. I refuse to accept that whitespace is text, so blank lines don't count. :-)
Here are the opportunities for removal that I found:
4 - Remove the IN keyword. That's the default for parameters (though I generally always include it in my code).
5 - Remove AUTHID DEFINER. Again, that is the default (definer's rights) and it means that this procedure will compile with the directly-granted privileges of the schema (roles need not apply).
7 - Remove entirely. The variable is not used. If it was, you could remove just ":= NULL" because by default variables are assigned the NULL not-value.
9 - The value will be displayed through line 19, so it is not needed here.
11 - A RETURN in a procedure? Huh? Yes, you can issue a RETURN in a procedure (and pipelined table function) that returns nothing but control. And it will do that. But as the last line in your procedure? No. That's what a procedure will do as a matter of course. Definitely not needed and not recommended.
That leaves just:
Now, if I had been a bit more relaxed in my puzzle rules and said "What text can be removed between lines 3 and 20?" you would probably would have had more fun - as you can see in the Twitter feed.
Because then you could remove lines 10 and 20, just keep line 19 to display the value, and even remove the TO_CHAR explicit conversion, because that number will be implicitly converted to a string when it is passed too DBMS_OUTPUT.PUT_LINE (which does not have an overloading for numbers). You could then also remove the OUT parameter modifier, since the second parameter is no longer being assigned a value in the procedure!
Did I miss anything? Let me know on the Twitter feed or in comments below. Have an idea for a puzzle of your own? I encourage you to throw it up on Twitter or you can also pass it along to me and I will publish it (giving you credit of course).
I will repeat the puzzle here. If you haven't already seen it on Twitter, please try to solve it yourself before looking at my answer.
What text can be removed from lines 3 though 12 in the code below so that after the anonymous block is executed, "121212" is still displayed on the screen?
White space
so you do not immediately
see my answers.
:-)
OK, let's dive in.
Notice, first of all, that I asked about text that can be removed, not lines. So you can remove entire lines or portions of lines. I refuse to accept that whitespace is text, so blank lines don't count. :-)
Here are the opportunities for removal that I found:
4 - Remove the IN keyword. That's the default for parameters (though I generally always include it in my code).
5 - Remove AUTHID DEFINER. Again, that is the default (definer's rights) and it means that this procedure will compile with the directly-granted privileges of the schema (roles need not apply).
7 - Remove entirely. The variable is not used. If it was, you could remove just ":= NULL" because by default variables are assigned the NULL not-value.
9 - The value will be displayed through line 19, so it is not needed here.
11 - A RETURN in a procedure? Huh? Yes, you can issue a RETURN in a procedure (and pipelined table function) that returns nothing but control. And it will do that. But as the last line in your procedure? No. That's what a procedure will do as a matter of course. Definitely not needed and not recommended.
That leaves just:
CREATE PROCEDURE my_proc (
arg1 NUMBER, arg2 OUT NUMBER)
IS
BEGIN
arg2 := arg1;
END;
Now, if I had been a bit more relaxed in my puzzle rules and said "What text can be removed between lines 3 and 20?" you would probably would have had more fun - as you can see in the Twitter feed.
Because then you could remove lines 10 and 20, just keep line 19 to display the value, and even remove the TO_CHAR explicit conversion, because that number will be implicitly converted to a string when it is passed too DBMS_OUTPUT.PUT_LINE (which does not have an overloading for numbers). You could then also remove the OUT parameter modifier, since the second parameter is no longer being assigned a value in the procedure!
Did I miss anything? Let me know on the Twitter feed or in comments below. Have an idea for a puzzle of your own? I encourage you to throw it up on Twitter or you can also pass it along to me and I will publish it (giving you credit of course).
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