Users connected to a group's user ID have certain permissions. This user ID can grant and revoke membership in the group. Also, this user would have ownership permissions over any tables in the database created in the name of the group's user ID.
It is possible to set up a database so that all handling of groups and their database objects is done by the DBA, rather than permitting other user IDs to make changes to group membership.
This is done by disallowing connection as the group's user ID when creating the group. To do this, the GRANT CONNECT statement is typed without a password. Thus:
GRANT CONNECT TO personnel
creates a user ID personnel. This user ID can be granted group permissions, and other user IDs can be granted membership in the group, inheriting any permissions that have been given to personnel, but nobody can connect to the database using the personnel user ID, because it has no valid password.
The user ID personnel can be an owner of database objects, even though no user can connect to the database using this user ID. The CREATE TABLE statement, CREATE PROCEDURE statement, and CREATE VIEW statement all allow the owner of the object to be specified as a user other than that executing the statement. This assignment of ownership can be carried out only by the DBA.