Karel Zak kirjutas K, 30.10.2002 kell 10:08:
>
> Hi,
>
> I read a presentation about Object-Oriented features in relation DBs.
> The nice are UDT (user defined type):
>
> CREATE TABLE person (
> name varchar(32),
> address ROW( street varchar(32),
> town varchar(32)),
> age int
> );
>
> INSERT INTO person VALUES ('Bill', ('Somestreet', 'Sometown'), 33);
>
> SELECT name, address.town FROM person;
>
>
> We have composite types in PostgreSQL and I think we can use it for this:
>
> CREATE TYPE addr AS (street varchar(32), town varchar(32));
> CREATE TABLE person (
> name varchar(32),
> address addr,
> age int
> );
>
>
> Comments? I nothinig found about OO in the current TODO.
I'm writing a small proposal for evoving inheritance and other OO
features in 7.4 and beyond. Will post once 7.3 is out.
> BTW, my
> examples are only small part of possible OO features, the others
> ideas are for example define PRIVATE/PUBLIC attributes in composite
> types
At least the "Third Manifesto" by Date et.al. claims that PRIVATE/PUBLIC
is better left to standard access control mechanisms (GRANT/REVOKE).
I agree to that.
> and methods, "SELECT p.name FROM person p WHERE p.pay->tax() > 100;"
The methods will probably have problems with syntax clashes with
existing stuff.
--------------
Hannu
