视频：Authorization (15min)

视频笔记:

Database Authorization

Users have privileges; can only operate on data for which they are authorized

• Select on R or Select (A1, ..., An) on R

• Insert on R or Select (A1, ..., An) on R
  

• Update on R or Select (A1, ..., An) on R
  

• Delete on R

Select View, Delete View.

Obtaining Privilege

• Relation creator is owner

• Owner has all previleges and may grant privileges

Grant privson Rto users 

[with Grant Option]

Revoking Privileges

Revoke privson RFrom users 

[Cascade|Restrict]

"Grant Diagram"

Cascade: Also revoke privileges granted from privileges being revoked (transitively), unless also granted from another source

Restrict: Disallow if Cascade would revoke any other privileges