Administrative Privileges and Roles 6 - Careful Access Control

Fine-grained access control
means that users can use functions and policies to implement more fine-grained security access control. If fine-grained access control is used, when a SQL statement ( select, insert, update, delete ) is issued on the client side , Oracle will automatically append a predicate (where clause) to the SQL statement and execute a new SQL statement. Through such control, different database users can return different data information when accessing the same table, as shown in the figure:
user scott black jones


policy emp_access

           
            database table emp

as shown in the above figure: through policy emp_access, users scott, black, jones When executing the same sql statement, different results can be returned. For example, when executing select ename from emp;, different results can be returned according to the actual situation.