Changing The Datatype of a column

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  13 years ago

  by shalinijennifer

  shalini

  , India

  Joined 13 years ago

  Hi,,

   

  How to change the datatype of a particular column in an existing table in Sql-Server thro coding... ie i want to do it in query analyser..I have Sql -Server 2005 in my System.My table has data in it..

  Thanks in Advance..

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  13 years ago

  by joe90

  J Alan

  , United Kingdom

  Joined 15 years ago

  It is possible... you simply use the "alter table" statement. However, you'd better double check that the column type alteration is allowed (ie castable) as it'll error out if its not- Sql Books Online should have this info.

  If this is not the case, you'll probably have to write a 'custom' routine that'll (a) extract all the data (b) change the column type and then (c) load the data back into the table with a customised column conversion function... Best to make a backup of the database in either case, just in case something happens. I've been caught out be this one on a previous occassion - one which I wouldn't like to have to redo ever again. Misery.

  Joe 

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