Re: Supertypes?

On Tue, Mar 27, 2001 at 03:58:39PM +0200, Christian Marschalek wrote:
> > Pg DOES support it!
> Oh... My fault :o)
>
> > However, it doesn't really have anything
> > to do with data redundancy. Data redundancy means storing
> > the same DATA in more than one table meaning that if it
> > changes in one table, you have to update all of the other
> > tables. That's not the same as inheritance which means you
> > can use a common base_table with additions to child tables as
> > necessary.
> Well we've learned that when you have lets say five tables which all
> contain name, adresse, city and so on you also have a form of
> redundancy... Can be wrong, though ;o)

there's also this construct -- i don't know the name --
exemplified below by using the table ADDR (very u.s.centric, i
know) as a DATATYPE in table PERSON:

create table addr(
street varchar(30),
city varchar(30),
state char(2),
zip char(5)
);
create table person(
loc addr, -- how about them apples?
phone char(10),
name varchar(30)
);
\d person
Table "person"
Attribute | Type | Modifier
-----------+-------------+----------
loc | addr |
phone | char(10) |
name | varchar(30) |

the trick, is, how do you insert data into person.addr?

--
It is always hazardous to ask "Why?" in science, but it is often
interesting to do so just the same.
-- Isaac Asimov, 'The Genetic Code'

will(at)serensoft(dot)com
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