Unique column constraint - SQL Server Forums

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Unique column constraint

Author

Topic

jmontgomery
Starting Member

3 Posts

Posted - 2008-06-06 : 22:45:01

I like to use the management console to design tables, but have
been unable to figure out how to add a unique column constraint.

I have a primary key defined in col1 and want to make col2, char(10),
unique, but keep col1 as the primary key.

I have tried the Check constraint menu path, but do not know how
to write the expression.

If I go along the Indexes/Key path, I am forced to change the primary
key which I do not want to do.

Can anyone help?

TIA, Joe

rmiao
Master Smack Fu Yak Hacker

7266 Posts

Posted - 2008-06-06 : 23:24:13

Expend table in ssms, right click on constraints and choose new constraint.

jmontgomery
Starting Member

3 Posts

Posted - 2008-06-06 : 23:32:47

Thx for the reply, but I need more help. I do not know how to
write the required espression to make col2 unique.

rmiao
Master Smack Fu Yak Hacker

7266 Posts

Posted - 2008-06-07 : 00:19:46

If you get check constraint there, delete it and close the page. Right click in table design and choose indexes/keys, choose column then pick unique key in type field. Save the table once done.

jmontgomery
Starting Member

3 Posts

Posted - 2008-06-07 : 10:14:15

Thx, I do now understand how to create the constraint which really
is an index via ssmc. I also was puzzled for a moment when I did not
see the new constraint listed under the table-constraint node, but
then looked under the index node & see it; IX_T3.

Thx again for your help --- Joe

Peace2007
Posting Yak Master

239 Posts

Posted - 2008-06-23 : 05:06:33

Unique constraint is actually an index in SQL2005 so it's intelligent enough to transfer it to the indexes.
for creating unique constraint you can also use the following query:
Alter table [tablename] add constraint [constraint name] Unique NonClustered (field name)

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