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  1. #1
    Join Date
    Dec 2002
    Posts
    9

    Arrow Unanswered: Using a varchar as a Primary Key VS. using an Identity

    Hello

    Currently, I am using a varchar "UserName" as a primary key instead of an Identity or GUID.

    System Info:
    When user's sign up they provide the "UserName" that is used as a PK.
    Creating a message board type web application.
    UserNames will never change.
    UserNames are used extensively as FK's in other Tables.
    We want to scale well.

    Does anyone know the implications?
    I understand Joins are faster on numerical values than strings but we will not be performing many joins.

    In my case is it better to use Identity as a PK or is it better to use a varchar for a "Users" table?

    Thanks
    jenn
    Last edited by jen6677; 01-07-05 at 03:36.

  2. #2
    Join Date
    Aug 2003
    Location
    Delft, The Netherlands (EU)
    Posts
    447
    I'm used to work with identity columns for almost every tabel, since the key shouldn't have any semantics (which could force the key to be changed), it must be unique of cource, and such a key is compact.

    On special occasions, however, I do not follow this golden rule. As you describe, your key will not change, it is unique, and you don't expect any join troubles; so I don't see problems to design your database this way.
    Make everything as simple as possible, but not simpler! - A. Einstein
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