Re: GRANT/REVOKE: Allow column-level privileges

I think we should pay attention to the sematic of table privs and column
privs.
Here is some examples.

1. role1 GRANT table priviledge SELECT on table S to role2.   role1 REVOKE column priviledge SELECT on column S(SNO)
fromrole2.
 
2. deal with circles in GRANT graph.

"kevin brintnall" <kbrint@rufus.net> wrote
> Fellow Hackers,
>
> I've been working on this item for a little while, and I'm starting to see
> some code come together.  I wanted to solicit some feedback before I got
> too far along to make sure I'm on the right track.
>
> Here's a rough overview of what I've done so far:
>
> -----------------------------------------------------------------
>
> PARSER:
>
>  * modified parser to accept SQL column privs syntax
>
>  * created a PrivAttr Node which holds ( priv, attr[] ) pairs.  Currently,
>    it's just a list of strings.  For example, when you call...
>
> GRANT SELECT, UPDATE (col1, col2) ON table1, table2 to grantee;
>
>    ... the parser creates a list of Nodes:
>
> ("select", NIL), ("update", ("col1", "col2"))
>
> SYSTEM CATALOG:
>
>  * add "attacl aclinfo[]" column to pg_attribute table and
Form_pg_attribute.
>  * add OID column to pg_attribute.  This permits dependencies to be
>    registered correctly in pg_shdepend.
>  * populated attacl column in existing pg_attribute bootstrap with NULLs
>  * allocated an unused oid for each of the pg_attribute rows that are
>    bootstrapped
>  * created an oid index on pg_attribute
>
>  * modified ExecuteGrantStmt to handle the PrivAttr structure instead of
>    the list of strings
>  * modified ExecuteGrantStmt to do a nested loop over all
>    (column,relation) pairs in the GRANT and find oids for all of the
>    attributes.
>
> PSQL COMMAND LINE:
>
>  * display column privileges with  "\d+ table"
>
> STILL LEFT TO DO:
>
>  * implement ExecGrant_Attribute() to modify pg_attribute
>  * verify query against column privileges in addition to table privileges
>  * register dependencies
>  * pg_dump column privileges
>
> -----------------------------------------------------------------
>
> I'd welcome any feedback on the design changes I've made, or any other
> potential snags I should watch out for.
>
> Thanks.
>
> --
>  kevin brintnall =~ <kbrint@rufus.net>
>
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