An Example you can test on Adventure works

select Name, GroupName, 2.7 as Constant from HumanResources.Department

ALTER TABLE TableName WITH NOCHECK
ADD CONSTRAINT DF_DefaultName DEFAULT ‘Default Value’ FOR ColumnName

Check it out !

Can someone please tell me how to specify a default constraint for an existing column?

Thanks in advance!!

Treasa

If that column you are trying to drop is used by any derived column, then you cannot drop it.

Example: in Example11 I created a table with out any derived column so I was able to drop column ename.

CREATE TABLE EXAMPLE11( EID INT , ENAME VARCHAR(10))
GO
ALTER TABLE EXAMPLE11
DROP COLUMN ENAME
GO

Result:Command(s) completed successfully.

Example2: In this example I created third column using first and second column, so when I try to drop second column, it gives me an error because second column in used in third column

CREATE TABLE EXAMPLE12 ( COLA INT, COLB INT , COLC AS COLA + COLB )
GO
ALTER TABLE EXAMPLE12
DROP COLUMN COLB
Go
Result: Msg 5074, Level 16, State 1, Line 1
The column ‘colc’ is dependent on column ‘COLB’.
Msg 4922, Level 16, State 9, Line 1
ALTER TABLE DROP COLUMN COLB failed because one or more objects access this column.

Hope this helps.
Thanks,
Imran.

i could not delete a column in a table through ‘ drop column’ option in ‘alter table’ query even though the column is not having any relationships or any other constraints.
please help me.

with regards,
adiraju

I think something is wrong with your blog software. The new blog post today is labeled as the 19th, but you posted it today, 3/21. Just wanted you to be aware.