Dear Sir or Madam,

I have your resume here in my hand and couldn’t help but notice that you have listed several versions of SQL Server in the experience section.  You may be an interviewee for a position in SQL Server, a .NET, or some other IT related discipline.  Regardless of which particular job you’re going for, I would like you to commit a few things to memory regarding the above-mentioned bullet point on your resume. Take these notes as reminders in the kind and helpful manner in which I mean them.

Data Types are Important

If you have touched SQL Server enough to warrant a line on page 1 of your resume, you need to know some of the extreme basics, such as data types.  Data types are the fundamental building blocks of databases, so take a few minutes to familiarize yourself with a few:

• char and varchar are slightly different. char is a fixed-length string type; varchar is a variable-length string type. However many characters you declare your char field or variable to have, that’s how many it will have. Set a char(4) equal to ‘a’, and the string will actually by ‘a   ‘. (Note their comparable Unicode types, nchar and nvarchar.)
• There are several different date and time types, each of which have a different precision and date range.
• Briefly familiarize yourself with the integer data types (part of the family of exact numerics, which also includes decimal and others).

SP_ means System Stored Procedure – Don’t use it

Don’t begin your stored procedures with sp_.  In addition to the reasons listed behind the link, a stored procedure whose name begins with sp_ will cause SQL Server to look in the master database for the SP, before it looks in the current database. That’s what we call a performance hit.  And certainly, don’t be like this guy. 

Database Objects are Important

Again, if your work with SQL Server warrants a page 1 bullet, it’d be an awfully good idea to know of a few database objects.

• Tables contain rows of data. Each column in a row has a name and a type.
• Indexes make tables more quickly searchable (for reads). Indexes come at a cost to writes (inserts and updates).
• Stored Procedures are saved in the database. They can accept input parameters, contain one or more statments, and return a value. Stored procedures can be called manually, or from applications or scheduled jobs.
• Triggers are similar to stored procedures, but they are event-driven: they are defined to execute when a specific event (such as an insert on a table) occurs.

Know What you Know

ORMs are not “faster” than SQL Server. Oracle is not “better” than SQL Server (or, necessarily, worse).  SQL Server 2005 didn’t make DTS “better” than SQL Server 2000. There is no SQL Server 2003. There is no SQL Server 2003. There is no SQL Server 2003. There is no SQL Server 2003. There is no SQL Server 2003. There is no SQL Server 2003. There is no SQL Server 2003. 

There is no SQL Server 2003. Know what you know, and don’t claim to know more. 

If you didn’t know most of the above, then you might think about removing SQL Server from your list of skills. 

Helpfully yours,

Jen McCown
MidnightDBA.com/Jen

P.S. To the folks I have interviewed thus far in 2012: None of this is actually directed at you, but you did inspire me (due to remembered interviews).  Good job, seriously.