sql - Why is "Deny" used in Data Control Language? -


i newly started learn basics of sql , while searching data manipulation language, data control language, data definition language didn't make sense.

as far understand, data control language has 3 keywords: grant, deny, revoke.

"grant" allows specified users things. "revoke" destroys security clearance specified users have.

however, don't understand "deny".

if users don't have security clearance (is there special term computer science?) specific database @ beginning, why programmer designs database "deny" user's clearance database? doesn't make sense.

could tell me why , use "deny"?

deny - in "deny access".

it means explicitly not allowing something. that's not same giving access , taking away access grant , revoke do, respectively.

consider may grant group access schema, sub-set of group want deny access subset of tables defined in schema. "deny" gives way so.


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