Common Mistakes in SQL Server - Part 4

Last week we discussed advantages of recompilation in Common Mistakes in SQL Server – Part 3. This week I will discuss the Null Value and how it can cause an issue!! What is NULL?  Null is the value which indicates the value is unknown. Null is different than zero or an empty string, as a zero or empty string indicates that the value is known (refer http://en.wikipedia.org/wiki/Null_%28SQL%29 for further reading.) Why should we avoid NULL values? In one of my previous projects I was asked to perform some tests and do analysis...

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Common Mistakes in SQL Server - Part 3

Last week in Common Mistakes in SQL Server - Part2 we discussed the advantages and disadvantages of using Identity columns. In this article I would like to shed some light on the advantages of recompile , and in what cases you should attempt recompilation! Generally, we create views and stored procedures (“proc” here after) to avoid the re-write  T-SQL  which is called often by an application or on ad-hoc basis. And, there...

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Common Mistakes in SQL Server - Part 2

Last week we discussed about whether to choose variable or fixed length data type and when to use when to use a Unicode data type like nchar or nvarchar in Common Mistakes in SQL Server – Part 1. Let’s discuss about the 2nd common mistake I have observed - using Identity column as primary key. Identity is a property which can be defined on an integer, decimal, numeric, small integer, big integer or tiny integer data type,...

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