Permissions are cumulative and DENY takes precedence. REVOKE removes GRANT and DENY permissions previously assigned. Because all users are members of public, you should DENY permissions to public only when you want to prohibit access by all database users.

Hope that helps.

Only the owner of the object has the permission/access on the object. Other users needs to be granted permissions by the owner/dba for access which is taken back by the REVOKE command.

If permission is not granted it means it is denied and there is no command to DENY any previlages.

thank you so much to replay ...but i need more explanation with example ,i did not get it yet.
thanks in advance.

you need to read books for all the details.

Dear Friend!

example as below

this used to changes the permissions on database
this DCL(DATA CONTROL LANGUGE)STATEMENT

*)GRANT---THIS IS ACCESS GARANTED ON PARTICLUR DB OR
USER
*)DENY----THIS IS PARTICLUR USER WAITING FOR ACCESS WHEN COMMETED THE DATA THEN PERMISSION ON DB

*)REVOKE--- THIS STATEMENT USE THE USER HAVE NO PERMISIONS

regards
Whizkidash