How can we create unique key

i am having one table
here username is there i want to create it as unique
how can

You need to create an unique constraint on the field.

[QUOTE=boreddy;29057]i am having one table
here username is there i want to create it as unique
how can[/QUOTE]

u can use the following script

ALTER TABLE [I]TableName[/I]
ADD CONSTRAINT uk_username UNIQUE KEY (UserName)


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Vikas Vaidya

hi, using constraint at creation table. other we can use alter the particular column....
ALTER TABLE TableName
ADD CONSTRAINT uk_username UNIQUE KEY (UserName)