A Check and Foreign Key Constraint Improves Query Performance

• pandeharsh

  Ten Centuries

  Points: 1106

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  December 9, 2013 at 2:49 am

  #1671839

  Great Article !

  Suppose I create some other type of constraint on table like allow only numeric then how will this type of constraint affect performance ?

  Suppose I create computed column on table.Then how it will affect performance .

  So I have ask 2 question .

  Thanks.

  [font="Verdana"]Regards
  Kumar Harsh[/font]

  :unsure:

• Jeff Moden

  SSC Guru

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  December 9, 2013 at 3:36 pm

  #1672151

  pandeharsh (12/9/2013)

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  Great Article !

  Suppose I create some other type of constraint on table like allow only numeric then how will this type of constraint affect performance ?

  Suppose I create computed column on table.Then how it will affect performance .

  So I have ask 2 question .

  Thanks.

  No one will know for sure. You must test it in your environment.

  As to the computed column, if you persist the column, then performance will likely be better because because it will be recalculated only for inserts or updates of the related columns and not for reads as a non-persisted computed column would be.

  --Jeff Moden

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  RBAR is pronounced "ree-bar" and is a "Modenism" for Row-By-Agonizing-Row.
  First step towards the paradigm shift of writing Set Based code:
  ________Stop thinking about what you want to do to a ROW... think, instead, of what you want to do to a COLUMN.

  Change is inevitable... Change for the better is not.
  

  ---

  Helpful Links:
  How to post code problems
  How to Post Performance Problems
  Create a Tally Function (fnTally)
  

• wasay_76

  SSC-Addicted

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  March 5, 2015 at 4:08 am

  #1781864

  Very good post !!!