Ajitesh Das wrote:
Hi Armin:
Thanks for your response. Now I understand what Thomas meant as key.
But the main issue is still there for me. Let's take CASE A as an example:
First of all, let me summarize what I have understood: Databases/data sources = { Da, Db , Dc, ...., Dn }
And I have a set of class-descrptors = { { a1, a2, a3 ....,ax},
{b1, b2, b3, ....,by},
:::::::::::::::::::
{n1, n2, n3, ....,nz}}
I want to map -> Class Descriptors ->{ a1,a2,::::,ax} to be mapped to [Da]
{ b1,b2,::::,by} to be mapped to [Db]
{ c1,c2,::::,cw} to be mapped to [Dc]
:::::::::::::::::::::::::::
{ n1,n2,::::,nx} to be mapped to [Dn]
and ai != bj != ck != .....!= nl
where i,j,k,l = 1,2 ....
Now my repository xml file will look like: Repository.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE descriptor-repository SYSTEM "repository.dtd"[
<!ENTITY internal SYSTEM "repository_internal.xml">
]>
<descriptor-repository version="1.0" isolation-level="read-uncommitted">
<jdbc-connection-descriptor jcd-alias="Da" ..../>
<jdbc-connection-descriptor jcd-alias="Db" ..../>
:::::
<jdbc-connection-descriptor jcd-alias="Dn" ..../>
<class-descriptor class="a1"
table="A1"
>
<attribute attribute-name="DB_NAME" attribute-value="Da"/>
:::::
</class-descriptor>
<class-descriptor class="b1"
table="B1"
>
<attribute attribute-name="DB_NAME" attribute-value="Db"/>
:::::
</class-descriptor> :::::::::::::::
::::::::::
</descriptor-repository>
And during runtime:
To access the data: My code will look like:
Object obj = ...
ClassDescriptor cld = MetadataManager.getInstance().getClassDescriptor(obj.getClass());
String db = cld.getAttribute("DB_NAME");
PersistenceBroker broker = PBF.createPersistenceBroker(new PBKey(db));
...
yep, that's what I mean. You arouse my curiosity ;-) Can you explain me why you need this?
But during the deployment time: [ what I have found from these tutorials ] I also need to create a schema file for the above case...similar to
src/schema/ojbtest-schema.xml.
Now question is:
Do I have to create:
Different build.properties and ojbmyapp-schema.xmls for each
Di Where i = 1,2,.....n Or Can I can create single build.properties and ojbmyapp-schema.xml
and and tell the Torque that create all a's in Da, all b's in Db ....and
n's in Dn.
sorry, I'm don't have much experience in using torque. I assume that you have to create a Di-schema.xml for each Di.
Thanks for your help and support. Ajitesh p.s: I am using your OJB in MMOG [ massive multiplayer online games ]
servers persistence engine, right now hosted in Taiwan and China and
supports 72k concurrent players .The performance is superb.!!!! Thank
you so much for providing OJB.
This sounds very interesting! Are you willing to post a link to your project? Maybe we can add your project to OJB 'references' projects.
regards, Armin
-----Original Message-----
From: Armin Waibel [mailto:[EMAIL PROTECTED] Sent: Monday, January 19, 2004 11:50 AM
To: OJB Users List
Subject: Re: Repository XML limitation and design question.
Hi Ajitesch,
Ajitesh Das wrote:
Hi Thomas:
Thanks for your reply. I have checked the DTD of repository xml, but could not find out the
way
to add "a key pointing to the associated ConnectionDescriptor in each
ClassDescriptor".
There is no such element or attribute.
Can you give me an example of that?
Think Thomas mean that you should use custom attribute element in class-descriptor:
<class-descriptor class="org.apache.ojb.broker.ComplexReferenceTest$TeamMember" table="CRT_MEMBER" >
<attribute attribute-name="DB_NAME" attribute-value="myJcdAlias"/>
<field-descriptor name="id" column="ROLE_ID" jdbc-type="INTEGER" primarykey="true" autoincrement="true" /> ...
Then you can lookup the attribute and do something like
Object obj = ...
ClassDescriptor cld = MetadataManager.getInstance().getClassDescriptor(obj.getClass());
String db = cld.getAttribute("DB_NAME");
PersistenceBroker broker = PBF.createPersistenceBroker(new PBKey(db));
...
You said in your mail that you have different repository files to load -
more info how to load different object metadata please see javadoc for MetadataManager.
regards, Armin
Thanks and regards Ajitesh
-----Original Message-----
From: Thomas Mahler [mailto:[EMAIL PROTECTED] Sent: Saturday, January 17, 2004 2:57 AM
To: OJB Users List
Subject: Re: Repository XML limitation and design question.
Hello Ajitesh,
Case A works without any problems. You simply define a set of ConnectionDescriptors and a set of ClassDescriptors in the Repository.
In each ClassDescriptor you have a key pointing to the associated ConnectionDescriptor.
Case B works too, but needs some consideration. At a given point in a time given class is associated with exactly one connectionDescriptor.
SO if you want to have a class mapped to several Connections you can
do
this only sequentially! So you you have to simply change the assigned ConnectionDescriptor key
of the ClassDescriptor at runtime. This is done through the Metadata API.
cheers, Thomas
Ajitesh Das wrote:
To all OJB gurus:
First of all this may not be a limitation on OJB what I have wrote
as
subject but it seems that there is no easy way to handle this.
Here is my problem :
I like to write a repository XML file [ please note a single
repository
file for each case] which captures the following conditions :
I have a set of Databases/data sources = { Da, Db , Dc, ...., Dn }
And I have a set of class-descrptors =
{ { a1, a2, a3 ....,ax},
{b1, b2, b3, ....,by},
:::::::::::::::::::
{n1, n2, n3, ....,nz}}
I want to map ->
Class Descriptors ->{ a1,a2,::::,ax} to be mapped to [Da]
{ b1,b2,::::,by} to be mapped to [Db]
{ c1,c2,::::,cw} to be mapped to [Dc]
:::::::::::::::::::::::::::
{ n1,n2,::::,nx} to be mapped to [Dn]
Case A:
Set (a)i and Set (b)j are disjoint.
That is: any ai != bj where i= 1,2...x
And j= 1,2,...y
Case B:
Set (a)i and Set (b)j are intersect each other.
That is: may be ai == bj where i= 1,2...x
And j= 1,2,...y
Has anybody did this before?
If this can not be done in a single repository xml ...is there any way it can be worked around?
Thanks
Ajitesh
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