Re: [gnome-db] Re: Gnome-db todo

[Andrew Hill <andru treshna com>]

Rodrigo Moya wrote:

> On Sat, 2002-04-06 at 04:20, Andrew Hill wrote:
>
> > Hi Rodrigo.
> >
> > Me, well no others, been working on intergrating bonddb with gnome-db. 
> > I've been a bit preoccupied with other things recently so havn't done a 
> > lot of coding.  Anyway, we've been running into a few problems when it 
> > comes to unique ids. Is there a way to get to the unique id for a record 
> > set currently implimented in libgda?. 
> no :-(
>
> But as it is really needed, let's talk about how to do it. For some
> databases (PostgreSQL, Oracle), it seems to be easy when just returning
> a table's data. But:
Hmm the difficult problems we create.  

> * how do you get the unique id of a row returned in a JOIN (SELECT ..
> FROM a, b)?
It depends on how the tables are joined and if it is a one to many, many 
to one or a many
to many relationship.  Normally it would be just the id for the first 
table (or the many
in one to many).  In a many to many relationship it would be both oids.  

At the moment i parse and modify the select statement i get to include 
things like
the oid i need. I create the sql string SELECT a.*,a.oid,b.* FROM a,b 
WHERE ...
from SELECT * FROM a,b WHERE ...

> * what can we do for DBMS's that don't have a ROWID or OID or whatever?
In my initial start i had a structure which just stores a list of 
primary keys, and or rowids
and oid's.  If the table didn't have a rowid or oid then it would fall 
back on using
table ids.


> > Thats been able to know what the 
> > unique id is, or pg_oid in the case of postgresql, for your current 
> > position in a record set?. and is there a way to work out on an insert 
> > what is the unique id generated for that insert?
> no :-(
>
> also, the same thing. We really need it, so how can we do it?
>
> cheers

There is a function for this in postgresql (PQoidValue(recordset)) and . 
Problem is i only know postgresql really well.  So i'm kinda fussy when 
it comes to working how to impliment some of this stuff into other 
databases.