sequence id

Hello all,

I am learning PostgreSQL and I found it really interesting. I am writing
some sql scripts to create some
tables and then add data via INSERT.

A question about SERIAL Data type. If I have a table definition like:

CREATE TABLE www_server (
id serial NOT NULL,
role char(5),
webserver varchar(25),
ip varchar(12),
hardware varchar(80),
software varchar(80),
checked DATE
);

And have an INSERT statement like:

INSERT INTO www_server
(role,webserver,ip,hardware,software,checked) VALUES
(
'www',
'webserver1',
'',
'Pentium II, 256 MBRAM',
'RedHat 7.3',
'2002-07-16'
);

my id which is a SERIAL will be incremented ok. But lets say I make
mistakes and want to delete from www_server everything. The next id
available will be which one was left previously. So If I run the INSERT
once I get 1 for my 'id'. If I delete and re-run my INSERT my 'id' is 2.

Do I need to do a VACUUM or how to restart from 1 ? I tried VACUUM; but
nothing worked. What worked was to DROP SEQUENCE and then the TABLE.

On the other hand is somehow reservated under PostgreSQL the name 'ID' for
column ?
If I create a table with ID works fine but selects are not working. If I
have 'id' for the column I can do SELECTs.

thanks
stefan