SQL conditional multiple ODBC connections

• sjcohn

  Newbie

  Points: 9

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  February 4, 2015 at 11:55 am

  #314916

  If I have 100 ODBC clients all submitting the following SQL at the same time how do I know that the SQL inside the conditional only gets executed once. It appear SQL Server is preventing it from happening but was curious how. Or do I need to add something to prevent it from happening.

  IF NOT EXISTS (SELECT name FROM sysobjects WHERE type='U' AND name = 'mytable)

  BEGIN

  CREATE table mytable (task int NOT NULL, first_name varchar(128), last_name varchar(128))

  END

• AlexSQLForums

  SSChampion

  Points: 14277

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  February 5, 2015 at 10:34 am

  #1775788

  Because you're telling the server to only create the table IF NOT EXISTS.

  IF NOT EXISTS is a conditional operation actually your code is 2 conditional expressions and a transaction in between.

  So the optimizer runs not exists 100 times but only 1 create table.

  Alex S