object-relational mapping

[Guest]

Hi. I'm trying to make the transition from VB6 to VB.NET and I just got to the data access design. My application (classic online store) is now fully object oriented. When I was faced with the questions of how and when I should populate my Client, Order, Product (etc) objects with the data stored in the database, I did some online research and I came accross the object-relational mapping paradigm
One problem that I'm having is that most of the articles online are about which vendor to use and not how to build your own ORM. Is there more to ORM than just retrieving data from a table (or a view) and populating the object's properties and/or updating the database with the object's properties
Does anyone know any good articles on how to build your own ORM
Does anyone have any practical experience with ORM (maybe specifically with Oracle)

Thank
Tiberiu M

 

[William Ryan eMVP]

Hi Tiberiu:

Hi. I'm trying to make the transition from VB6 to VB.NET and I just got to

the data access design. My application (classic online store) is now fully
object oriented. When I was faced with the questions of how and when I
should populate my Client, Order, Product (etc) objects with the data stored
in the database, I did some online research and I came accross the
object-relational mapping paradigm.

There can be a lot more than just basic mapping. We have a forum on
devbuzz dedicated to ORM which you might find helfpul. This is also just a
personal opinion, but Deklarit http://www.deklarit.com/hdefault.aspx has a
product that is without a doubt one of the most impressive programs I've
ever seen. It's ORM on steriods with a bunch of friends on steriods too
with a millino dollar bank accout. It's a phenomenal program. LLBLGen also
has a program which is excellent. I favor Deklarit because it supports SQL
CE and I know more about it, but they are both superb products and I'll
guarantee that you'll be better off with either than rolling out your own.

One problem that I'm having is

that most of the articles online are about which vendor to use and not how
to build your own ORM. Is there more to ORM than just retrieving data from a
table (or a view) and populating the object's properties and/or updating the
database with the object's properties?
It can be very simple or it can be very complex. Deklarit for instance will
verify and validate business rules as an example of something more that it
does.

Does anyone know any good articles on how to build your own ORM?

I'd start out at MS's Code Generation site http://www.codegeneration.net/
http://www.ericjsmith.net/codesmith/
http://www.c-sharpcorner.com/Code/2003/Oct/BasicStampGen.asp
These others should also be helpful.


Kathleen Dollards book on Code Generation in Microsoft .NET
http://www.apress.com/book/bookDisplay.html?bID=212 is essentially dedicated
to this subject as a whole with Chapter 6 being dedicated directly do ORM
and DataAccess. She's quite critical of her own work saying she made it too
complex. I disagree and think it's a little complex but it makes up for it
in being thorough and interesting and it's not 'too' complex that an average
programmer can't understand it. If you buy this book you'll like it, but
if you want to roll out your own ORM, then Chapter 6 is priceless

Does anyone have any practical experience with ORM (maybe specifically

with Oracle)?
Once again, let me digress to Deklarit...it's just a really great
product....

 

[Guest]

Wow. So much help! Great. Thanks.