Re: Row security policies documentation question - Mailing list pgsql-general

From David G. Johnston
Subject Re: Row security policies documentation question
Date
Msg-id CAKFQuwZNTJAj3mmuYjxk3j8sMawrOBSOSrSABO4aOr-cG=YBuA@mail.gmail.com
Whole thread Raw
In response to Row security policies documentation question  ("Alexander M. Sauer-Budge" <ambudge@alum.mit.edu>)
Responses Re: Row security policies documentation question
List pgsql-general
On Tue, May 31, 2016 at 4:59 PM, Alexander M. Sauer-Budge <ambudge@alum.mit.edu> wrote:
Hello,

Section 5.7. on Row Security Policies (https://www.postgresql.org/docs/current/static/ddl-rowsecurity.html) for 9.5 says:
 
[...]
 

CREATE POLICY user_policy ON users
    USING (user = current_user);

---

I’m trying understand the example as it references both an `accounts` table and a `users` table which isn’t defined. Is this a mishmash of example fragments or should the CREATE POLICY statement reference the `accounts` table instead of `users`? Specifically, what does `user` reference in the statement "CREATE POLICY user_policy ON users USING (user = current_user);”?

 
Is this a table column in a `users` table the example doesn’t define or does PostgreSQL keep track of what user/role inserted a row and allow policies to use it?

​It assumes the user can envision a trivial "users" table having at least a column named "user" that represents the user's name/id and which the names of said users are identical to those assigned to them in the PostgreSQL database and accessible via the "pg_authid" catalog (rolname) and its related views: namely "pg_user" (usename).

​​So, in effect the following works, and returns a single row.

SELECT *
FROM users
JOIN pg_user ON (user = usename)
WHERE user = current_user;

David J.​


pgsql-general by date:

Previous
From: "Alexander M. Sauer-Budge"
Date:
Subject: Row security policies documentation question
Next
From: carlos@lpis.com
Date:
Subject: plql and or clausule