Database design help!

[ultim]

I am creating a simple user management system database design.

Each is user belongs to a user group. There are two main user groups; admin and users.

The part im finding differcult is the users group can also split into sub user groups. So a user can belong to a admin, user, sub user group.

How do i design my tables to accommodate that?

What i got so far:

USER
pkuserid
fkadminid (nullable)
fkusergroup (nullable)
fksubusergroup (nullable)

ADMINGROUP
pkadminid
name

USERGROUP
pkusergroup
name

SUBUSERGROUP
pksubuserid
fkpkusergroup (nullable)
name

Is there a better way to store the information?

 

[Vai]

Have a table for users, a table for all groups (inc subgroups) then another table which can link user id's to group id's?

 

[ultim]

that would work, but there are different fields related to different groups. I might able to combine main and sub user groups into one table.