Sunday, August 17, 2008

How to Drop a Column

How to Drop a Column
  • Discover whether there is a constraint;
DECLARE @ConstraintName NVARCHAR(50);
SELECT @ConstraintName = [name]

FROM sys.objects o

WHERE o.[parent_object_id]=OBJECT_ID('Schema.TableName')

AND o.type='D'

AND o.[name] LIKE '%First5LettersOfColumnName%'

  • If there is, remove it;
IF NOT (@ConstraintName IS NULL)

   EXECUTE ('ALTER TABLE Schema.TableName 
   DROP CONSTRAINT ' + @ConstraintName)
GO

  • Remove the column
IF EXISTS(SELECT * FROM sys.columns WHERE [name]='ColumnName 
  
AND [object_id]=OBJECT_ID('Schema.TableName'))


      ALTER TABLE
Schema.TableName

      DROP COLUMN ColumnName;

GO


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