The FROM Clause

You can specify the PUBLIC keyword to revoke the specified fragment-level privileges from PUBLIC, thereby revoking the privileges from all users to whom the privileges have not been explicitly granted, or who do not hold a role through which they have received the privileges.

If you enclose user or role in quotation marks, the name is case sensitive and is stored exactly as you typed it. In an ANSI-compliant database, if you do not use quotation marks around user or around role, the name is stored in uppercase letters by default, although you can set the ANSIOWNER environment variable to preserve lowercase characters in owner specifications.

When you include a role in the FROM clause of REVOKE FRAGMENT, the specified fragment privilege is revoked from that role. Users who have that role, however, retain any fragment privileges they hold that were granted to them individually or to PUBLIC.