在Oracle上授予角色

Question

I'm creating a database with oracle and php for an assignment and i have to show the use of roles. i created a new role called employee and assigned it to a new user called employee1

CREATE ROLE read_only;
GRANT create session TO read_only;
GRANT select ON workson TO read_only;
GRANT select ON employee TO read_only;
GRANT select ON project TO read_only;
GRANT select ON department TO read_only;

CREATE ROLE employee;
GRANT read_only TO employee;
GRANT update ON employee TO employee;
GRANT insert ON workson TO employee;

Create user employee1 identified by qwerty1;
GRANT employee TO employee1;

Why does using any selects when connected as employee1 say there is no such table. select * from employee says there is no table. Did i form my roles wrong or something?

Answer 1

Your grants appear to be fine. Assuming that the employee1 user does not own the employee table, you would need to qualify the table name in your SELECT with the owner of the table. For example, if we're talking about the employee table that is owned by the hr user, you'd need to

SELECT *
  FROM hr.employee;

If you don't want to have to qualify your table names, you have a couple of options. First, you can create synonyms. You can create a private synonym in the employee1 schema that applies only to the employee1 user

CREATE SYNONYM employee
   FOR hr.employee;

or you can create a public synonym that applies to all users

CREATE PUBLIC SYNONYM employee
   FOR hr.employee;

The second option would be to set your current_schema after connecting.

ALTER SESSION SET current_schema=hr;

If you have an appropriate synonym in place or if you've set the current_schema, you don't have to prefix the table name with the owner of the table.