Question

I’m specifying a field, username, as unique for my application. As a part of the install the user is able to specify a table prefix if they choose. But the unique index that is automatically created does not inherit that table prefix.

    CREATE TABLE IF NOT EXISTS ".$prefix."users (
          id int(11) NOT NULL AUTO_INCREMENT,
          username varchar(50) UNIQUE NOT NULL,
          PRIMARY KEY (id)
        ) ENGINE=MyISAM  DEFAULT CHARSET=utf8 COLLATE=utf8_bin;

The index that is automatically created is just named username. If there is a second installation to the same database there would be a conflict.

Is there a way to have the index created with the prefix or do I need to delete the index after the table is created and recreate it with the prefix?

Answer 1

You can supply an explicit index name like so:

CREATE TABLE IF NOT EXISTS ".$prefix."users (
      id int(11) NOT NULL AUTO_INCREMENT,
      username varchar(50) NOT NULL,
      PRIMARY KEY (id),
      UNIQUE $unique_index_name (username)
    ) ENGINE=MyISAM  DEFAULT CHARSET=utf8 COLLATE=utf8_bin;