Drop a column from table problem (SQL Server 2008)

Question

Unable to delete [U_Family] column from table below :

Table CREATE script:

CREATE TABLE [dbo].[Users](
    [U_Id] [int] IDENTITY(101,1) NOT NULL,
    [U_Name] [nvarchar](50) NULL,
    [U_Family] [nvarchar](50) NULL,
 CONSTRAINT [PK_Users] PRIMARY KEY CLUSTERED 
(
    [U_Id] ASC
),
 CONSTRAINT [IX_UserIdUnique] UNIQUE NONCLUSTERED 
(
    [U_UserId] ASC
)
) ON [PRIMARY]
GO

CREATE UNIQUE NONCLUSTERED INDEX [IX_Users(UserId)] ON [dbo].[Users] 
(
    [U_Id] ASC
)
INCLUDE ( [U_Name],
[U_Family]) ) ON [PRIMARY]
GO

error message :

'Users' table - Unable to modify table. The index 'IX_Users(UserId)' is dependent on column 'U_Family'. ALTER TABLE DROP COLUMN U_Family failed because one or more objects access this column.

I know that the problem is because of this index :

CREATE UNIQUE NONCLUSTERED INDEX [IX_Users(UserId)] ON [dbo].[Users] 
(
    [U_Id] ASC
)
INCLUDE ( [U_Name],
[U_Family])) ON [PRIMARY]
GO

but I never found a syntax to edit this index and remove [U_Family] from included columns.

I cannot delete this index because it is used by a foreign key constraint that I should not remove it.

any solution ????

thanks in advance.

score 5 · Accepted Answer · answered Apr 20 '11 at 07:57

In SQL Server 2008, you should be able to "re-create" your index and drop the existing one in a single command - try this:

CREATE UNIQUE NONCLUSTERED INDEX [IX_Users(UserId)] 
  ON [dbo].[Users]([U_Id] ASC) 
  WITH DROP_EXISTING

The WITH DROP_EXISTING should drop the "old" index with the included columns. Once that command has been run, you should be able to drop your column from the table.

score 0 · Answer 2 · answered May 20 '13 at 10:59

I used sys.indexes to delete the index and then drop the column:

DECLARE @sql VARCHAR(max)

SELECT @sql = 'DROP INDEX ' + idx.NAME + ' ON tblName'
FROM sys.indexes idx
INNER JOIN sys.tables tbl ON idx.object_id = tbl.object_id
INNER JOIN sys.index_columns idxCol ON idx.index_id = idxCol.index_id
INNER JOIN sys.columns col ON idxCol.column_id = col.column_id
WHERE idx.type <> 0
    AND tbl.NAME = 'tblName'
    AND col.NAME = 'colName'

EXEC sp_executeSql @sql
GO

ALTER TABLE tblName
DROP COLUMN colName

score 0 · Answer 3 · answered Oct 24 '17 at 13:21

I found this solution and worked for me:

DECLARE @ConstraintName nvarchar(200)
SELECT @ConstraintName = Name FROM SYS.DEFAULT_CONSTRAINTS WHERE 
PARENT_OBJECT_ID = OBJECT_ID('__TableName__') AND PARENT_COLUMN_ID = (SELECT 
column_id FROM sys.columns WHERE NAME = N'__ColumnName__' AND object_id = 
OBJECT_ID(N'__TableName__'))
IF @ConstraintName IS NOT NULL
   EXEC('ALTER TABLE __TableName__ DROP CONSTRAINT ' + @ConstraintName)
IF EXISTS (SELECT * FROM syscolumns WHERE id=object_id('__TableName__') AND 
name='__ColumnName__')
   EXEC('ALTER TABLE __TableName__ DROP COLUMN __ColumnName__')

Just replace __TableName__ and __ColumnName__.

score 0 · Answer 4 · answered Apr 20 '11 at 07:55

0

You will have to drop the index IX_Users and create a new one without U_Family.

answered Apr 20 '11 at 07:55

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Drop a column from table problem (SQL Server 2008)

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