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From Dibyendu Majumdar <dibye...@mazumdar.demon.co.uk>
Subject Some questions regarding Derby Store
Date Fri, 01 Feb 2008 23:17:52 GMT

I am reading the javadoc documentation and also referring to the  
source code to get an understanding, but it would greatly help me if  
you would answer following questions:

1. I am trying to understand the  
org.apache.derby.iapi.services.context package and what it is used  
for. So far my understanding is this:

a) It is a mechanism for sharing information across multiple modules  
without having to pass parameters.
b) It is a mechanism for stashing away values so that a module can  
get back the stashed values when it is called again.
c) It is a mechanism for associating values with a thread.
d) It is a mechanism for passing error information and cleaning up on  

The javadoc comments explain how it works, but not really tell why it  
is necessary.

2. Is it possible to have more than one Transaction active in a  
thread? It seems to me from looking at RAMTransactionContext that  
there is a notion of current transaction context. Is this a reason  
why it is necessary to support the nested transaction concept?

3. Following two questions are related to the  
org.apache.derby.iapi.services.monitor package.

a) Is my understanding correct that each module must know what other  
module it depends upon and try to boot the required module? Thus, the  
Monitor system does not inject dependencies, each module needs to  
find any modules it depends upon?
b) Is a Service a synonym for a database instance on disk?

Thank you very much for your help.



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