based access controlOracle角色基于访问控制（oraclerole）
Role Based Access Control（RBAC） is a computer system security model used to control access to a system’s resources by allowing administrators to assign different roles to different users within the system. RBAC ensures that users assigned to a certain role can only access the specific resources they need in order to do their job.
RBAC is particularly useful for databases and other applications that require confidential information to be kept secure. By assigning roles to users, the system can ensure that only those users who are authorized to access the resources can do so.
In order to define roles, RBAC uses several security attributes, such as tasks and operations, privileges, and user profiles. Tasks and operations refer to a set of operations that a user can perform. Privileges define the level of access a user has, such as read, write, and execute permissions. And user profiles are created to specify the exact permissions for the user, for example giving them only read access to a certain resource.
When it comes to Oracle databases, roles can be created using the GRANT and REVOKE statements. The GRANT statement is used to grant access to the required resources to a certain user, based on their role. The REVOKE statement is then used to remove the access granted with the GRANT statement.
For example, if we have a table WebUsers and we want to give some users read-only access to the table, we can create a role called WebUserReaders and assign it to the users. We then use the GRANT statement to give the role access to the table:
GRANT SELECT ON WebUsers TO WebUserReaders;
Now the users with the WebUserReaders role will have access to the table.
RBAC helps to ensure that users can only access the resources that are necessary for them to do their job. It also helps to ensure that users do not have access to resources that they should not have access to, which helps to keep the system secure. In Oracle databases, roles are easily created using the GRANT and REVOKE statements.
