relational mapping ...

[T.Mo]

i am new to AtomsFramework, but trying to upgrade my current project using AtomsFramework:)

Here ask a very simple question. In ms sql server, we all know that we can do autodeletion/update by mapping different tables with foreign keys. Say, A Customer may have a few orders, and if this customer got deleted, all the orders shall be deleted automatically.

How can I achieve this by using this framework? I dont want to use the ms sql server features to achieve this, as i may use another database.

[T.Mo]

I believe i have figured how.

Now, another question. if i apply lazy loading to collections, how to load them when I need them?

THanks!

[Richard Banks]

Have a read of this previous forum topic:

http://sourceforge.net/forum/forum.php?thread_id=1229818&forum_id=208150

Let me know if you still have questions.

- Richard

[Nobody/Anonymous]

Many Thanks Richard! I do have some more questions:)

Here comes one:

While trying to use method CCursor.loadPersistentObject or loadObject in C#, i always have following error msg:

Argument '1': cannot convert from 'ref Helper.DefSettings' to 'ref AToMSFramework.CPersistentObject'

But what I see from online tutorial in your web site cant help me on this ... Please let me know which part goes wrong..

My Code:

defs = new DefSettings();
                    cursor.loadPersistentObject(ref defs);

I also tried loadObject method. Give me same error.

[Richard Banks]

You should definitely be using loadObject.  loadPersistentObject is meant to be an internal use method.

Regardless your exception message is probably a good indicator...
Argument '1': cannot convert from 'ref Helper.DefSettings' to 'ref AToMSFramework.CPersistentObject'

Even though DefSettings inherits from CPersistentObject C# requires that you explicitly cast the object first (don't ask me why - I don't know).

Try this:
CPersistentObject cp;
cp = defs;
cursor.loadObject(ref cp);
defs = (DefSettings) cp;

- Richard

[T.Mo]

Ok, I modified my code as following:

CPersistentObject objDf;
defs = new DefSettings();
objDf = defs;
cursor.loadObject(ref objDf); // only one object.
defs = (DefSettings)objDf;

And i still got similar messages:
The best overloaded method match for 'AToMSFramework.CCursor.loadObject(ref object)' has some invalid arguments
Argument '1': cannot convert from 'ref AToMSFramework.CPersistentObject' to 'ref object'

Cant pass the compiler! The only time i can get my code compiled is to use Object (not CPersistentObject!) to init a variable, and pass down as "ref myObj". However, when get into execution, the application will tell me "no mapping for Object class....".

[Richard Banks]

I'll check it out - I always use VB, so my C# is a bit rusty.  It might take me a little bit to figure it out.

[T.Mo]

Finally, manage to solve it now. Get some hints from your reply just now.

The working code:

CPersistentObject objDf;
defs = new DefSettings();
objDf = defs;
cursor.loadPersistentObject (ref objDf); // only one object.
defs = (DefSettings)objDf;

For C#, shall use loadPersistentObject  method, otherwise wont work. Maybe this is an illegal use of the framework ...