O/R Mapping tool like Apple has.....for .NET?!?!  
Author Message
fak119





PostPosted: Fri Aug 29 09:07:15 CDT 2003 Top

Net Framework >> O/R Mapping tool like Apple has.....for .NET?!?!

Hi!

I post this text 1 year ago. But no one really could give
me an answer. This is the text that I posted long time ago:


I have a fundamental question about
The way .NET handles the object orientated way of
Persistence. I am coming from JAVA and WebObjects (Apple)
World and I am looking for a convenient way of working
with objects without seeing any SQL statements only
objects. I have used that approach for years on the
WebObjects Platform (Enterprise Object Framework) and in
Java recently (Container Managed Persistence). I am
looking for something like that in the Microsoft world.

As far as I understand Microsoft does not distinguish
between the Object Model and the Relational Model. The
main difference is that the Object model allows n : m
relationships and the Relational does not allow them. Here
a small example to visualize the problem:

Example:
There is a Patient object with following Attributes

String patientGUID;
String name;
Int age;
Hashtable diseases; (or some other Container like
Collection or Array)


And there is a Disease Object

String diseaseGUID;
String name;


In the object Model there is relation between Patient and
Disease where the patient has his diseases but on the
other site one disease can belong to 1..* patients. (n :
m)

That n : m relationship can not exist within a relational
database without a link table that contains the
connections between the tables: Patient and Disease.

Now, I would like to connect the object Model containing
TWO Entities (Patient, Disease) with the relational
database (containing THREE tables). Then I want to work
with my objects; e.g. create new diseases connect them to
existing patients by putting the diseases into the array
or create new Patients and connect them with already
existing diseases or just change a Patients name. When I
am finished I just want to say SAVECHANGES and the
database is updated accordingly including all link table
entries.

So all I have to care about are my objects and the
relations between them, some invisible layer does all the
dirty work like building SQL, converting the data types
and caching. So if I fetch a Patient with a specified GUID
I do not have to care about fetching his diseases. They
are fetched automatically. If there are too many Diseases
I do not care some kind of algorithm handles that problem
in such a way that if I have to search all of them for
something they are simply there. They are loaded on demand
(lazy evaluation)

Supposing that the disease has a further connection with
some DiseaseType Object/Table and that table has an
attribute/column "Description" I can access it by typing
the following code:

TextField1.Text = currentDisease.type().description()

Please note that to retrieve the description value I did
only fetch the Patient. The diseases and its types were
fetched automatically.

Is something like that possible or am I excepting too much
of the .NET?

-------------------------------------------------------------------




This tool should be a mixture between Microsoft Visio (I mean ORM modelling)
and a good object-to-relational mapping tool.



Is something like that NOW available????


thx!


gicio

DotNet131  
 
 
gicio





PostPosted: Fri Aug 29 09:07:15 CDT 2003 Top

Net Framework >> O/R Mapping tool like Apple has.....for .NET?!?! Hi!!


for a better understanding you should check this .pdf:


http://developer.apple.com/documentation/WebObjects/UsingEOModeler/UsingEOModeler.pdf


gicio







> Hi!
>
> I post this text 1 year ago. But no one really could give
> me an answer. This is the text that I posted long time ago:
>
>
> I have a fundamental question about
> The way .NET handles the object orientated way of
> Persistence. I am coming from JAVA and WebObjects (Apple)
> World and I am looking for a convenient way of working
> with objects without seeing any SQL statements only
> objects. I have used that approach for years on the
> WebObjects Platform (Enterprise Object Framework) and in
> Java recently (Container Managed Persistence). I am
> looking for something like that in the Microsoft world.
>
> As far as I understand Microsoft does not distinguish
> between the Object Model and the Relational Model. The
> main difference is that the Object model allows n : m
> relationships and the Relational does not allow them. Here
> a small example to visualize the problem:
>
> Example:
> There is a Patient object with following Attributes
>
> String patientGUID;
> String name;
> Int age;
> Hashtable diseases; (or some other Container like
> Collection or Array)
>
>
> And there is a Disease Object
>
> String diseaseGUID;
> String name;
>
>
> In the object Model there is relation between Patient and
> Disease where the patient has his diseases but on the
> other site one disease can belong to 1..* patients. (n :
> m)
>
> That n : m relationship can not exist within a relational
> database without a link table that contains the
> connections between the tables: Patient and Disease.
>
> Now, I would like to connect the object Model containing
> TWO Entities (Patient, Disease) with the relational
> database (containing THREE tables). Then I want to work
> with my objects; e.g. create new diseases connect them to
> existing patients by putting the diseases into the array
> or create new Patients and connect them with already
> existing diseases or just change a Patients name. When I
> am finished I just want to say SAVECHANGES and the
> database is updated accordingly including all link table
> entries.
>
> So all I have to care about are my objects and the
> relations between them, some invisible layer does all the
> dirty work like building SQL, converting the data types
> and caching. So if I fetch a Patient with a specified GUID
> I do not have to care about fetching his diseases. They
> are fetched automatically. If there are too many Diseases
> I do not care some kind of algorithm handles that problem
> in such a way that if I have to search all of them for
> something they are simply there. They are loaded on demand
> (lazy evaluation)
>
> Supposing that the disease has a further connection with
> some DiseaseType Object/Table and that table has an
> attribute/column "Description" I can access it by typing
> the following code:
>
> TextField1.Text = currentDisease.type().description()
>
> Please note that to retrieve the description value I did
> only fetch the Patient. The diseases and its types were
> fetched automatically.
>
> Is something like that possible or am I excepting too much
> of the .NET?
>
> -------------------------------------------------------------------
>
>
>
>
> This tool should be a mixture between Microsoft Visio (I mean ORM
modelling)
> and a good object-to-relational mapping tool.
>
>
>
> Is something like that NOW available????
>
>
> thx!
>
>
> gicio
>
>
>


 
 
Dino





PostPosted: Fri Aug 29 12:32:34 CDT 2003 Top

Net Framework >> O/R Mapping tool like Apple has.....for .NET?!?! see response in the other newsgroup you posted to.



> Hi!!
>
>
> for a better understanding you should check this .pdf:
>
>
>
http://developer.apple.com/documentation/WebObjects/UsingEOModeler/UsingEOModeler.pdf
>
>
> gicio
>
>
>
>
>


> > Hi!
> >
> > I post this text 1 year ago. But no one really could give
> > me an answer. This is the text that I posted long time ago:
> >
> >
> > I have a fundamental question about
> > The way .NET handles the object orientated way of
> > Persistence. I am coming from JAVA and WebObjects (Apple)
> > World and I am looking for a convenient way of working
> > with objects without seeing any SQL statements only
> > objects. I have used that approach for years on the
> > WebObjects Platform (Enterprise Object Framework) and in
> > Java recently (Container Managed Persistence). I am
> > looking for something like that in the Microsoft world.
> >
> > As far as I understand Microsoft does not distinguish
> > between the Object Model and the Relational Model. The
> > main difference is that the Object model allows n : m
> > relationships and the Relational does not allow them. Here
> > a small example to visualize the problem:
> >
> > Example:
> > There is a Patient object with following Attributes
> >
> > String patientGUID;
> > String name;
> > Int age;
> > Hashtable diseases; (or some other Container like
> > Collection or Array)
> >
> >
> > And there is a Disease Object
> >
> > String diseaseGUID;
> > String name;
> >
> >
> > In the object Model there is relation between Patient and
> > Disease where the patient has his diseases but on the
> > other site one disease can belong to 1..* patients. (n :
> > m)
> >
> > That n : m relationship can not exist within a relational
> > database without a link table that contains the
> > connections between the tables: Patient and Disease.
> >
> > Now, I would like to connect the object Model containing
> > TWO Entities (Patient, Disease) with the relational
> > database (containing THREE tables). Then I want to work
> > with my objects; e.g. create new diseases connect them to
> > existing patients by putting the diseases into the array
> > or create new Patients and connect them with already
> > existing diseases or just change a Patients name. When I
> > am finished I just want to say SAVECHANGES and the
> > database is updated accordingly including all link table
> > entries.
> >
> > So all I have to care about are my objects and the
> > relations between them, some invisible layer does all the
> > dirty work like building SQL, converting the data types
> > and caching. So if I fetch a Patient with a specified GUID
> > I do not have to care about fetching his diseases. They
> > are fetched automatically. If there are too many Diseases
> > I do not care some kind of algorithm handles that problem
> > in such a way that if I have to search all of them for
> > something they are simply there. They are loaded on demand
> > (lazy evaluation)
> >
> > Supposing that the disease has a further connection with
> > some DiseaseType Object/Table and that table has an
> > attribute/column "Description" I can access it by typing
> > the following code:
> >
> > TextField1.Text = currentDisease.type().description()
> >
> > Please note that to retrieve the description value I did
> > only fetch the Patient. The diseases and its types were
> > fetched automatically.
> >
> > Is something like that possible or am I excepting too much
> > of the .NET?
> >
> > -------------------------------------------------------------------
> >
> >
> >
> >
> > This tool should be a mixture between Microsoft Visio (I mean ORM
> modelling)
> > and a good object-to-relational mapping tool.
> >
> >
> >
> > Is something like that NOW available????
> >
> >
> > thx!
> >
> >
> > gicio
> >
> >
> >
>
>


 
 
Michael





PostPosted: Fri Aug 29 13:54:54 CDT 2003 Top

Net Framework >> O/R Mapping tool like Apple has.....for .NET?!?!


> see response in the other newsgroup you posted to.
>


>> > This tool should be a mixture between Microsoft Visio
>> > (I mean ORM modelling)
>> > and a good object-to-relational mapping tool.
>> >
>> > Is something like that NOW available????
>> >
>> > gicio

I'm interested in the answer also. What other groups?

--
Michael Lang, MCSD