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Home -> Community -> Usenet -> c.d.o.tools -> PL/SQL Tip of the Month
From the PL/SQL Pipeline - a free internet community for PL/SQL developers
around the world. Check the pipeline for tips & hints, lively discussions,
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http://www.revealnet.com/pipeline.htm
March's Tip of the Month - One Way In, One Way Out
If you want to write code that is easy to debug, understand and maintain, then you should follow this rule:
One Way In, One Way Out
This means that for any procedure, function or loop, there should be only one way to initiate that program element, and one way to (successfully) terminate that program element.
Consider this FOR loop:
FOR monthnum IN 1 .. 12
LOOP
calc_monthly_sales (monthnum)
IF monthnum > 8
THEN
EXIT;
END IF;
END LOOP;
While there is only one way to start the loop, the loop terminates in one
of two ways: the loop index reaches 12 and stops, or the EXIT statement is
executed. This is misleading code. I consider a FOR loop a promise: I will
let this code iterate as specified and then continue. An EXIT inside the
FOR loop means that my program can "bail out" under a variety of
circumstances. In this simple example, the various paths are clear. On the
other hand, if your program has 500 lines of gnarly code your ability to
trace the execution path will diminish greatly.
So follow these simple rules:
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