I've seen it done in Java - Moving objects around.
Yes it is a lot of work.
Object to SQL mapping can be a lot of work. There are figures around that
say this can eat up to 40% of project time when done by hand coding.
Myles.
> -----Original Message-----
> From: Peter G Jones [SMTP:[EMAIL PROTECTED]]
> Sent: Wednesday, 16 February 2000 00:10
> To: Multiple recipients of list delphi
> Subject: Re: [DUG]: Marhsalling: COM vs Corba
>
> I'm trying to be a purist here but it would be really nice to have a
> persistent object that could move around the network. Does Java have
> anything like this? Maybe Jade? Maybe just learn RPG and use the AS/400
> (no objects/no worries)?
>
> I spose I could create the empty object on the client and pass it to the
> server when I want it loaded or saved. Any other manipulation is then
> local
> to the client. Better still, if the server could return some formated
> data
> from a method and the client can fillin attributes of the instance.
>
> I think I'll end up with 5 tiers, 2 on the client and 2 on the server.
> Client tiers will be presentation, a pure object and a data-to-object
> translater. On the server I would have the opposite data-to-object
> translater and the database itself.
>
> Seems like a lot of work ? Comments?
>
> >From: "Nic Wise" <[EMAIL PROTECTED]>
> >Reply-To: [EMAIL PROTECTED]
> >To: Multiple recipients of list delphi <[EMAIL PROTECTED]>
> >Subject: Re: [DUG]: Marhsalling: COM vs Corba
> >Date: Mon, 14 Feb 2000 18:12:53 +1300
> >
> > > Imageine I have a server process that creates a object and returns the
> > > interface to the client. With COM, if I call methods and set
> properties
> >on
> > > this instance I get network traffic cause the object is alive on the
> >server,
> > > not the client. Correct ?
> > >
> > > With Corba (or COM), is there a way of avoiding this network traffic?
>
> >IE,
> > > can the object be magically transported to the client rather than just
> a
> > > reference to it?
> >
> >Nope - what happens if you server is compiled C++ code running on an
> >UltraSPARC 20?? Not gonna work on your little PIII 500, right?! (OK, bad
> >example, 'cos then it would _have_ to be a CORBA object, but still....)
> >
> >technically could work for COM, being its WinTel only, but you can kiss
> >scalability and platform neutrality goodbye.
> >
> >So, in general, no, you can't do this. CORBA 2.3 (Visibroker 4.0) has
> >Objects By Value which is something to do with this, but I havn't used or
> >looked into it much yet. Delphi only has CORBA v2.2 (Visi 3.3/3.4)
> >
> >I find the best way to get 'around' this is to pass records or structs,
> eg
> >in CORBA IDL:
> >
> >struct EmployeeRecord {
> > string name;
> > string phone;
> > string irdNumber;
> >};
> >
> >interface Employee {
> > attribute EmployeeRecord employee;
> >};
> >
> >For example. Then you can get the record (one fairly big hit on the
> >network), mess with it, and fire it back (another big hit on the
> network),
> >rather than have hit-change-hit, hit-change-hit, hit-change-hit which is
> a
> >LOT slower.
> >
> >HTH.
> >
> >N
> >
> >
> >
> >-------------------------------------------------------------------------
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> > Website: http://www.delphi.org.nz
>
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