Beginning SQL

The CASCADE option tells the DBMS that a REVOKE of the GRANT OPTION should cause a ripple down the
chain and also revoke any privileges issued because of the GRANT OPTION.
Suppose Jim issues a GRANT to Sue WITH GRANT OPTION:
GRANT SELECT
ON tblPersonnel
TO usrSue
WITH GRANT OPTION
Sue now issues a GRANT to Frank:
GRANT SELECT
ON tblPersonnel
TO usrFrank
Jim now issues a REVOKE to Sue:
REVOKE SELECT
ON tblPersonnel
FROM usrSue CASCADE
In this case, both Sue and Frank lose their SELECT privilege on tblPersonnel because Jim placed the
CASCADE option on the REVOKE statement.
Assume that Jim issued the same GRANT to Sue, and Sue issued the same GRANT to Frank. Jim later issues
the following REVOKE:
REVOKE SELECT
ON tblPersonnel
FROM usrSue RESTRICT
In this case, the REVOKE fails and issues an error warning Jim that there are privileges cascading down
from the GRANT that he issued, and that he may be revoking privileges that he doesn’t intend to revoke.
If Jim does decide to revoke Sue’s privileges, he can simply issue the REVOKE again with the CASCADE
option. The RESTRICT option is just a way to let a user know that the REVOKE will cause a cascade
REVOKE.
In addition, the SQL2 syntax now includes the ability to specify the privilege in the REVOKE GRANT statement
instead of just revoking all GRANT privileges. Consider the following statement:
REVOKE GRANT OPTION ON INSERT, DELETE
ON tblPersonnel
FROM usrSue CASCADE
SQL Security
This statement revokes the ability to GRANT OPTION on these privileges but does not take away the privileges
themselves.
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