[WIP] patch - Collation at database level

Hello,

I'm sending part of the code that I've done and is available for reviewing
and I'm asking for your comments and some help because I'm new to
PostgreSQL.

Proposal: http://archives.postgresql.org/pgsql-hackers/2008-05/msg00857.php

The code contains changes of parser, pg_collation catalog, parsenodes.h for
CREATE COLLATION... and DROP COLLATION statements.

Questions that I would like to know answers:

1) Should I move DROP statement from DropCollationStmt to DropStmt? Some
statements are seperated and some are included in DropStmt? Is there any
reason for that?
2) What type should all names in CREATE and DROP statement in gram.y have?
I've chosen qualified_name but I know it's not the best choice.
3) All collations are created from existing collations. How do I ensure that
the collation already exists? Is there any possibility to define it in
gram.y?
4) For further functionality development is there anything more needed than
adding T_CreateCollationStmt and T_DropCollationStmt to
/src/backend/tcop/utility.c, and write functionality into collation.c?
5) Also can you look at the pg_catalog and tell me if anything is wrong with
it?

Thank you for all your replies in advance.

Regards

Radek Strnad