Replacing PUBLIC with Specified Users
If a table owner grants a privilege to PUBLIC, the owner cannot revoke
the same privilege from any specific user. For example, assume PUBLIC has
default Select privileges on your customer table. Suppose
that you issue the following statement in an attempt to exclude ted from accessing your table:
REVOKE ALL ON customer FROM ted;
This statement results in ISAM error message 111, No record
found, because the system catalog tables (syscolauth or systabauth) contain no table-level privilege
entry for a user named ted. This REVOKE operation does
not prevent ted from keeping all the table-level privileges
given to PUBLIC on the customer table.
To restrict table-level privileges, first revoke the privileges with the
PUBLIC keyword, then re-grant them to some appropriate list of users and roles.
The following statements revoke the Index and Alter privileges from all users
for the customer table, and then grant these privileges
specifically to user mary:
REVOKE INDEX, ALTER ON customer FROM PUBLIC; GRANT INDEX, ALTER ON customer TO mary;