Check constraint. Boolean unqiue value check.

• Sinh Dinh

  Right there with Babe

  Points: 729

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  May 7, 2009 at 2:03 pm

  #137363

  I'm trying to figure out the best way make sure that there is only one "active" row in a table at one time.

  CREATE TABLE Test (

  ID Int,

  AmountMin int,

  AmountMax int,

  isActive bit )

  Data in table.

  ID AmountMin AmountMax isActive

  1 100 200 0

  2 100 300 1

  3 200 550 0

  4 300 700 0

  How would I be able to make sure there's only one isActive true flag at any given time.

  Thanks.

• Jetro

  Ten Centuries

  Points: 1257

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  May 7, 2009 at 2:35 pm

  #990692

  Hi,

  have a look at this article MSDN

  There you'll find an example how to use a check constraint with a function.

  I hope this helps 🙂

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