Case-insensitive unique index in Rails/ActiveRecord?

Question

I need to create a case-insensitive index on a column in rails. I did this via SQL:

execute(
   \"CREATE UNIQUE INDEX index_users_on_lower_email_index 
    O         


        

Answer 1

I think you need column name(s) as below

   add_index "users", [email], {:name => "index_users_on_lower_email_index", :unique => true }

And you have to make email field in database with proper Case Insensitive collation, that way your index will be also case insensitive.

depending of db engine which you are using it syntax may be different but

alter table [users] alter column [email] varchar(250) collate utf8_general_ci ...

and when you add index to this column it will be case insensitive.