Does your SQL Smell? The free "119 SQL Code Smells" eBook might help you sniff it out (and fix it)

simple talk - 119 SQL Code Smells

Written with advice, help or contributions from over 25 SQL professionals
Download the free PDF: from Red Gate

Once you've done a number of SQL code-reviews, you'll be able to identify signs in the code that indicate all might not be well. These 'code smells' are coding styles that, while not bugs, suggest design problems with the code. In this PDF, Phil's put together 119 of those code smells so you can see what to avoid and why.

Kent Beck and Massimo Arnoldi seem to have coined the term 'CodeSmell' in the 'Once And Only Once' page of www.C2.com, where Kent also said that code ‘wants to be simple’. Kent Beck and Martin Fowler expand on the issue of code challenges in their essay ‘Bad Smells in Code’, published as Chapter 3 of the book ‘Refactoring: Improving the Design of Existing Code’ (ISBN 978-0201485677).

Although there are generic code smells, SQL has its own particular habits that will alert the programmer to the need to refactor code...

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One can be a bit defensive about SQL code smells. I will cheerfully write very long stored procedures, even though they are frowned upon. I’ll even use dynamic SQL on occasion. You should use code smells only as an aid. It is fine to ‘sign them off’ as being inappropriate in certain circumstances. In fact, whole classes of code smells may be irrelevant for a particular database. The use of proprietary SQL, for example, is only a code smell if there is a chance that the database will be ported to another RDBMS. The use of dynamic SQL is a risk only with certain security models. Ultimately, you should rely on your own judgment. As the saying goes, a code smell is a hint of possible bad practice to a pragmatist, but a sure sign of bad practice to a purist.

In describing all these 119 code-smells in a booklet, I’ve been very constrained on space to describe each code smell. Some code smells would require a whole article to explain them properly. Fortunately, SQL Server Central and Simple-Talk have, between them, published material on almost all these code smells, so if you get interested, please explore these essential archives of information.

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nuff said...