SQL Server Primary Keys

I have a database table architecture question.  Is it better to design a primary key with the standard pk_id where it is an "int" or a guid?
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Mike EghtebasDatabase and Application DeveloperCommented:
GUID uses 4 time more resources compared PK (int).

Generally, GUID has to be avoided unless the operation intended the database to perform requires it. More more see: http://blog.codinghorror.com/primary-keys-ids-versus-guids/

And because GUID is random, it is not suitable as cluster key thus not efficient as cluster key. And when a new GUID gets created it causes further fragmentation and causes bad performance.

HuaMin ChenProblem resolverCommented:
Int is OK, and you can also declare it as an identity, like
CREATE TABLE new_employees
 id_num int IDENTITY(1,1),
 fname varchar (20),
 minit char(1),
 lname varchar(30)

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Vitor MontalvãoMSSQL Senior EngineerCommented:
First thing that you should ask is: "Do I really need a GUID?"
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Arifhusen AnsariBusiness Intelligence Developer and AnalystCommented:
As Expert says the GUID uses more resource to store the data.

 it took little more time to read the that column data, if you have large numbers of rows.

 If you declare it as the Primary column it will create the index on it and if you select Int as a type , Indexes will be more faster and efficient.
Scott PletcherSenior DBACommented:
Int is preferred over GUID, for the reasons noted above.  But, whenever possible, a natural PK from actual data column(s) in the table is vastly preferred.

But what is absolutely critical to understand is that the PK should not automatically be the clustering index key.  The clustering key(s) are the most critical factor in table performance.  Whenever possible, use a natural clustering key that matches the data usage of the table.

For example, if a given table is always searched on state and city, cluster the table by state and city, not by some arbitrary number!  If you also want to add an identity to act as a simple PK that's fine, but it should not be the clustering key in this example.

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CipherISAuthor Commented:
Thank You.
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Microsoft SQL Server 2005

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