rails error making field unique

Question

I get this when trying to run the migration:

Mysql2::Error: Duplicate entry 'repeat' for key 'index_industries_on_name':

CREATE UNIQUE INDEX `index_industries_on_name` ON `industries` (`name`)

Migration is add_index :industries, :name, {:unique => true}

Answer 1

You have two or more rows with "repeat" as the industry name. You cannot make the name column of your industries table unique until you fix this.