Drop a column from table problem (SQL Server 2008) - sql

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.

Answer 1

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.

Answer 2

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

Answer 3

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

Answer 4

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__.