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How to write the mapping file ?

Edward Chen
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Joined: Dec 23, 2003
Posts: 798
I am using hibernate IDE, I found some confusing.

class A {
B b;
B[] b_array;
String[] string_array;
}
class B{...}

---- say "B b";
One solution is
<one-to-one name="b" class="B"/>
anther solution is
<component name="B" ... />

How to write the mapping file ?
miguel lisboa
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Joined: Feb 08, 2004
Posts: 1281
one thing i like in this forum is the fact that members arent rude as in other java forums; this said, i dont want to rtfm you, but i guess browsing this would help you a lot


java amateur
Edward Chen
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Joined: Dec 23, 2003
Posts: 798
The thing is this, I use Exadel ORMstudio to map object.

I try the simple class just like above. The solution ORMStudio gava to me is "component ..." but I read the book and online tutorial, I think it should be "<one-to-one ..." . You see this difference. This is my confusing. So I post it here to ask for help. Do you think it is rude action ?

I did a lot of homework before I post this question.

Thanks
miguel lisboa
Ranch Hand

Joined: Feb 08, 2004
Posts: 1281
Do you think it is rude action

you misunderstood me!
i never intented to call you rude; i was refering some posters that are rude when answering newbie questions, that's all
miguel lisboa
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Joined: Feb 08, 2004
Posts: 1281
imagine you'v a class Person and a class Adress; you can map them both as entities - with database identifier; but, if you use what HiA authors call fine grained objects, you may as well map Adress as a component (a hibernate notion).
Read this - they explain it:
David Harkness
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Joined: Aug 07, 2003
Posts: 1646
Do you want to be able to access the B objects outside of As? If so, they are entities and will have their own identifier. With that, you can load a B without loading its A. If the B is more like an Address (to use Miguel's example), you may only want to access it from the A. In that case, make it a component.

The problem is that tools cannot know your intended use of the objects, so it simply picks a method to use.
Edward Chen
Ranch Hand

Joined: Dec 23, 2003
Posts: 798
Originally posted by David Harkness:
Do you want to be able to access the B objects outside of As? If so, they are entities and will have their own identifier. With that, you can load a B without loading its A. If the B is more like an Address (to use Miguel's example), you may only want to access it from the A. In that case, make it a component.

The problem is that tools cannot know your intended use of the objects, so it simply picks a method to use.


you mean, B is only accessed through A , B is sealed in A ---> component
B is indepent object, ---> one-to-one ...

When "component", actually it is ONE table.
When "one-to-one", it is TWO tables.

My understanding is right? Thanks for your help.
Edward Chen
Ranch Hand

Joined: Dec 23, 2003
Posts: 798
Originally posted by miguel lisboa:
imagine you'v a class Person and a class Adress; you can map them both as entities - with database identifier; but, if you use what HiA authors call fine grained objects, you may as well map Adress as a component (a hibernate notion).
Read this - they explain it:


Thanks for your help. the link you post is very helpful.

Forget about the "rude" things, We are all in the same wonderful java community.
 
It is sorta covered in the JavaRanch Style Guide.
 
subject: How to write the mapping file ?