CODEWITHSUNDEEP
mysqlsqldatabaseuniquealter
Ya Fa Su
Ya Fa Su

Reputation: 160

MySQL change a column to unique

I have a database table that saved users profile information. Sometimes when users register, they get duplicated with an extra column with same records, sometimes not.

So, I wonder if I put Unique on the column Email to make sure the user don't dup when register.

I think it should be something like this:

ALTER TABLE users ADD UNIQUE idx_row_unique(email);

But in case the Unique give error, how do I undo it?

Just scare that after I change it, I don't know how to undo it.

Upvotes: 0

Views: 592

Answers (2)

tjfo
tjfo

Reputation: 1189

I'd export the table structure and data first. That way if you need to put it back, you have the SQL right there.

Upvotes: 0

GeorgeVremescu
GeorgeVremescu

Reputation: 1253

If there are duplicate emails, the alter table should fail. So you're safe with that!

Upvotes: 2

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