ALTER TABLE admin_members ADD PRIMARY KEY (name, admin_group);

This creates a composite primary key, forcing all parings of a name and group number to be unique. So Glarawyn cannot be a member of group 1 multiple times, but Glarawyn can be a member of group 1 and 2.

This change doesn't really change anything; it just prevents possibly annoying duplication. Also, admin_members looks to be the only default table without a primary key set, which I just don’t get because there is a primary key right there without adding extra data.