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From John Embretsen <John.Embret...@Sun.COM>
Subject Re: [WWD] Review of Final Chapters (5 and 6)
Date Wed, 03 May 2006 11:00:14 GMT
Stanley Bradbury wrote:

>    Attachment: ReviewPDF_wwdCh5and6rv1.0.zip
>                ReviewSRC_wwdCh5and6rv1.0.zip
> 
> Initial reveiw files (rv 1.0) for Working With Derby Ch 5 and 6
>  >> Please review and send comments to derby-user@db.apache.org.  Please 
> code the subject line with '[WWD]'

I have a couple of small comments to the "Activity notes" in Activity 4 
in the Ch. 5 and 6 PDF, v1.0, available for download at 
http://issues.apache.org/jira/browse/DERBY-913. I am sending these 
comments to derby-user only.

<quote 1 from "Activity notes", p.6 (8)>
A client program is often created to allow database access and updates 
from multiple computers on the network.
</quote>

I don't think this statement is correct. It is not the "client program" 
that allows access from multiple computers, it is the server framework 
that does this. Would you like to rephrase?


<quote 2 from "Activity notes", p.6 (8)>
Derby's two architectures have caused confusion for some new Derby 
users. They mistakenly think that embedded is a single user 
configuration. Not true. The embedded driver supports multiple 
simultaneous connections, performs locking and provides performance, 
integrity and recoverability.
</quote>

I think this is still confusing. I think you should add a comment saying 
that the embedded driver must *not* be used to access the same database 
from more than one JVM simultaneously. The multi-user capabilities you 
are describing are (as far as I know) only valid if all users use the 
same JVM/Derby system (i.e. the same instance of the embedded driver), 
or if no users using different JVMs/Derby systems access the same 
database at the same time.


-- 
John



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