Обсуждение: COMPUTED BY fields or equivalent?

Hi all,


I use Interbase (starting on PostgreSQL) which has a concept of

CREATE TABLE My_Table
(
  First_Name VARCHAR(15),
  Last_Name  VARCHAR(15),
  Full_Name  VARCHAR(30) COMPUTED BY(First_Name || ' ' || Last_Name)
}

Full_Name is now a read only field in My_Table.


Is there an equivalent in PostgreSQL.

I would also be interested in hearing if this concept exists in other
RDBMS's.

TIA.


Paul...


--

plinehan  x__AT__x  yahoo  x__DOT__x  com

C++ Builder 5 SP1, Interbase 6.0.1.6 IBX 5.04 W2K Pro

Please do not top-post.

Paul Ganainm <paulsnewsgroups@hotmail.com> writes:
> I use Interbase (starting on PostgreSQL) which has a concept of

> CREATE TABLE My_Table
> (
>   First_Name VARCHAR(15),
>   Last_Name  VARCHAR(15),
>   Full_Name  VARCHAR(30) COMPUTED BY(First_Name || ' ' || Last_Name)
> }

You could do that with a view (if you don't want the derived field to be
physically stored on disk) or with a trigger (if you do).

            regards, tom lane

tgl@sss.pgh.pa.us says...


> > I use Interbase (starting on PostgreSQL) which has a concept of
> >   Full_Name  VARCHAR(30) COMPUTED BY(First_Name || ' ' || Last_Name)


> You could do that with a view (if you don't want the derived field to be
> physically stored on disk) or with a trigger (if you do).


Yes, indeed - and both of these solutions would work perfectly fine with
Interbase/Firebird.


I was just wondering if PostgreSQL implemented a COMPUTED BY feature or
equivalent (as I said, I would also be curious about other RDBMS's).


Thanks for your input so far.


Paul...


>             regards, tom lane


--

plinehan  x__AT__x  yahoo  x__DOT__x  com

C++ Builder 5 SP1, Interbase 6.0.1.6 IBX 5.04 W2K Pro

Please do not top-post.