SQL Scales: 2 - T-SQL Programming

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Little disciplines to remember when programming T-SQL.

  • Structured programming practices:


    • Find what varies and encapsulate it

    • Keep your procedures small; let each do one thing and do it well

    • Favor Clarity over Cleverness


      • Clever solutions are being scrapped in IT shops all over the world every day and replaced with less "clever" solutions that are understandable and maintainable.


    • Usually Consistent is better than Better. (Sad but true.)

    • Simply formatted header comments are maintained; complex formats are not. Example of a simple header:



/*
Note on what the proc does.

usage:
    exec usp_MyProc

created YYYYMMDD by username
updated YYYYMMDD by username - chg# xxxx: description
*/


  • In Reporting queries, prefer #Temp Tables over @Table Variables.


    • Table variables are easier to pass around, but the optimizer always assumes there is only one row. For larger temp storage (>100 rows), use #temp tables which produce real statistics.


  • Set vs. Select - prefer Set


    • Assume @x = "flower"

    • "Set @x = (select something)" will set @x = null if (select something) returns nothing

    • "Select @x = something" will leave @x = "flower" if (select something) returns nothing


  • Common Abbreviations / Naming:


    • Amt, Nbr, Pct

    • List names should end with "List".


  • Solution Tension:


    • Do the simplest thing that will work

    • Solve the problem fully (don't settle for shallow/lazy/half-baked)

    • Avoid Premature Optimization

    • If you've got an 80% solution in your head, go with it. Don't wait for the "perfect" idea.


  • Remember, future-you will either bless or curse current-you based on what you create today. Let's make future-you happy :^)


 

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