NOT NULL and what happens if a data type isn't given a value when a row is added

• Golfer22

  SSCrazy

  Points: 2256

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  February 10, 2012 at 9:41 pm

  #98608

  When a data type is defined as NOT NULL, what happens when new rows are created? Will a new row not be created (e.g., throw an error) if data is attempted to be inserted in that column/value that was declared/defined as NOT NULL?

• Gail Shaw

  SSC Guru

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  February 11, 2012 at 3:44 am

  #1445881

  If data is specified to be inserted into the not null column then that's fine. I suspect you meant what happens if data is not specified for a not null column.

  In that case..

  Msg 515, Level 16, State 2, Line 1

  Cannot insert the value NULL into column <column name>, table <table name>; column does not allow nulls. INSERT fails.

  Gail Shaw
  Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
  SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

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