title: Smart Date Key Vs Date Data Type in Date Dimension Table
body: <p>I'm currently designing a database and will employ a Date Dimension table that will contain the various possible groupings a user may wish to report on e.g. financial year, quarter etc. This will be role played through views to create versions for Order Date, Cancellation Date etc and then merged with other Dimension tables.</p>
  <p>Common database design theory advocates a smart key of form YYYYMMDD that is used to merge with other tables, however, I wonder if this is still valid. My understanding is that SQL Server, which is what I'm using, uses a data type of Date which is three bits over an integer of 4 bits.</p>
  <p>Assuming that I do not require records that would identify records where date is &quot;Unknown&quot;or &quot;Not Available&quot; etc, is there any reason to use an integer smart key over date?</p>
  <p>Thank you for your assistance.</p>