Thread: Methods in pgsql
I've read somewhere that PostgreSQL is an ordbms or a oodbms. After reading Bruce Momjian's book "PostgreSQL: Introduction and Concepts" it's apparent to me that the only feature that seems to be an object oriented one is table inheritance. I didn't see a method implementation anywhere in the book. Did Momjian omitted the topic or it is indeed nonexistent in the current version? Efrain
Attachment
Efrain Caro writes: > I've read somewhere that PostgreSQL is an ordbms or a oodbms. After reading > Bruce Momjian's book "PostgreSQL: Introduction and Concepts" it's apparent > to me that the only feature that seems to be an object oriented one is table > inheritance. I didn't see a method implementation anywhere in the book. Did > Momjian omitted the topic or it is indeed nonexistent in the current > version? Methods don't exist. In general, a complete SQL implementation is the priority of the project; OO features tend to have been neglected a bit. -- Peter Eisentraut peter_e@gmx.net http://yi.org/peter-e/
Then, may I conclude that methods are not part of the SQL92 standard? ----- Original Message ----- From: "Peter Eisentraut" <peter_e@gmx.net> To: "Efrain Caro" <betsemes@hotmail.com> Cc: "PostgreSQL general mailing list" <pgsql-general@postgresql.org> Sent: Friday, September 29, 2000 4:06 PM Subject: Re: [GENERAL] Methods in pgsql > Efrain Caro writes: > > > I've read somewhere that PostgreSQL is an ordbms or a oodbms. After reading > > Bruce Momjian's book "PostgreSQL: Introduction and Concepts" it's apparent > > to me that the only feature that seems to be an object oriented one is table > > inheritance. I didn't see a method implementation anywhere in the book. Did > > Momjian omitted the topic or it is indeed nonexistent in the current > > version? > > Methods don't exist. In general, a complete SQL implementation is the > priority of the project; OO features tend to have been neglected a bit. > > -- > Peter Eisentraut peter_e@gmx.net http://yi.org/peter-e/ > >
"Efrain Caro" <betsemes@hotmail.com> writes:
> I've read somewhere that PostgreSQL is an ordbms or a oodbms. After reading
> Bruce Momjian's book "PostgreSQL: Introduction and Concepts" it's apparent
> to me that the only feature that seems to be an object oriented one is table
> inheritance. I didn't see a method implementation anywhere in the
> book.
You could get some of that effect with triggers associated with
particular child tables. SQL92 doesn't really have any notion of
computation associated with a table, as opposed to computation
associated with rows being put into or taken out of a table,
so there's not a lot of scope for true methods associated with a
table viewed as an object. But you could use triggers to vary
what happens when you store or update rows in different tables.
Note also that there's a pretty complete abstract-data-type facility
for the data values being kept in tables. If the objects you want
to deal with are more along the lines of items in tables instead of
tables themselves, there's plenty of room to define a collection of
datatypes that have method-ish behavior. I'm not sure you could claim
that Postgres "supports" that, since it doesn't offer a handy notation
or anything, but it doesn't get in the way either.
regards, tom lane
Efrain Caro writes: > Then, may I conclude that methods are not part of the SQL92 standard? They aren't, but the current standard is SQL99, which has this sort of thing. -- Peter Eisentraut peter_e@gmx.net http://yi.org/peter-e/
Is there an online source through which I can get the SQL99 standard specification? ----- Original Message ----- From: "Peter Eisentraut" <peter_e@gmx.net> To: "Efrain Caro" <betsemes@hotmail.com> Cc: "PostgreSQL general mailing list" <pgsql-general@postgresql.org> Sent: Friday, September 29, 2000 7:48 PM Subject: Re: [GENERAL] Methods in pgsql > Efrain Caro writes: > > > Then, may I conclude that methods are not part of the SQL92 standard? > > They aren't, but the current standard is SQL99, which has this sort of > thing. > > -- > Peter Eisentraut peter_e@gmx.net http://yi.org/peter-e/ > >