inet versus text for ip addresses

The PostgreSQL inet datatype stores an holds an IP host address, and
optionally the identity of the subnet it is in, all in one field.
This requires 12 bytes.

Using my "random" data of approximately 8000 IP addresses collected
during previous polls, I've found the average length of an IP address
is 13.1 bytes. An integer requires 4 bytes.

First question: Why not store an option to store just an IP address?
That should require less than the 12 bytes for inet.

On to the real question:

The existing tables are:

create table recount_ips
(
ipid serial not null,
ipaddress inet not null,
primary key (ipid)
);

create unique index recount_ips_ip_address on recount_ips
(ipaddress);

create table recount_iptopolls
(
pollid integer not null,
ipid integer not null,
primary key (pollid, ipid)
);

alter table recount_iptopolls
add foreign key (pollid)
references recount_polls (pollid) on update restrict on delete
restrict;

alter table recount_iptopolls
add foreign key (ipid)
references recount_ips (ipid) on update restrict on delete
restrict;

I think a better solution is one table:

create table recount_iptopolls
(
pollid integer not null,
ipaddress inet not null,
primary key (pollid, ipaddress)
);

alter table recount_iptopolls
add foreign key (pollid)
references recount_polls (pollid) on update restrict on delete
restrict;

It removes a table and the associated primary key, and removed a
foreign key from the modified recount_iptopolls table.

Comments?
--
Dan Langille : http://www.langille.org/