Locking Level

Jackson wrote:

1. I'm just wondering what type of Level does PostgreSQL locking mechanizm is.

http://www.postgresql.org/docs/postgres/mvcc.htm

2. Is there a way to tell PostgreSQL to generate a unique id to a field in a table?

http://www.postgresql.org/docs/faq-english.html#4.16.1

Regards,
Ed Loehr