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mrsaif
Starting Member
43 Posts |
 Posted - 2006-09-08 : 03:26:20
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| Hi, I have a table Accounts with column userName, currently there is not any uniqu Key contarint on that column. I wnat to add Unique Key contraint on that column. How should i do that?Muhammad Saifullah |
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eyechart
Master Smack Fu Yak Hacker
3575 Posts |
Posted - 2006-09-08 : 03:42:09
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try this:ALTER TABLE accounts ADD CONSTRAINT ak_accounts__username UNIQUE (username) that will create a unique key called ak_accounts__username on username column of the accounts table.-ec |
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mrsaif
Starting Member
43 Posts |
Posted - 2006-09-08 : 03:57:20
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| Thanks, some existing records violates the unique key constraints how to fix those... ? means how to use no check option ??Muhammad Saifullah |
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eyechart
Master Smack Fu Yak Hacker
3575 Posts |
Posted - 2006-09-08 : 04:02:28
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quote:
Originally posted by mrsaif
Thanks, some existing records violates the unique key constraints how to fix those... ? means how to use no check option ??
no, you need to find the duplicates and deal with them first. how to find dupes? good question:SELECT username FROM accountsGROUP BY username HAVING COUNT(*) > 1 -ec |
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Applying Unique Key constaint on exisiting column