Re: Re: [HACKERS] Postgresql OO Patch

> > 
> >    Therefore: for object system you need complete other types of object
> >    identification numbers.
> 
> I agree, that's why I have suggested an implied super-class "Object" for
> all postgresql objects. Then you could do "SELECT ** FROM object WHERE
> oid=?". The ability to place an index over sub-class hierarchies (in
> this case oid for all objects) would get the good performance.

 I can not believe, that this will result in a good performance. This
column (object identifier) would need an index to cover ALL objects
...  and this index will be growing and now image a system with about
1.000.000 objects and now try to insert a new object. Indices on such
large mount of value maybe a problem.

 On the other hand: the solution you mentioned can be done without an
implied table - which would be a special solution. The application can
create the "super"-table and should be responsible for it.

> 
> Actually, postgres can have arrays of oids which is the ODBMS way of
> handling associations. Last I looked there are some contrib functions
> for doing things like ...
> 
> CREATE TABLE foo( bar [] );
> CREATE TABLE bar( ... etc);
> SELECT bar.** from bar, foo where array_in(bar.oid, foo.bar)  and
> foo.oid=?". In other words, to retrieve all the objects in a list.
> (forget the actual function name).

 Have you ever create a 1:n association with about 800 entries ?
Actually I do not know, how many entries such an array may
have. Unlimited ? How do I remove an entry, how do I delete an 
entry. I may have a closer look at that.
 
> >  - no support to inform the client about changes inthe database !
> 
> Havn't even looked at that.
> 

 But here again an active system may be build on top of the system we
already have:

 - update, insert, deletes are catched via triggers (on commit)
   these trigger functions do retrieve the object-id of the objects
   changed and write the result into a special table.

 - another software has notification on this special table and managed
   the ip-commuication to the clients.


 Marten