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From Kathey Marsden <kmarsdende...@sbcglobal.net>
Subject Re: [jira] Commented: (DERBY-458) Make it clear the difference between EmbedConnection and Networked Connection
Date Mon, 22 Aug 2005 17:21:21 GMT
TomohitoNakayama wrote:

> Hello.
> I think this is a question , which may raise up document and code issue.
> //Reading spec of DRDA at opengroup (http://www.opengroup.org/) is
> best shortcut ?

I've never heard that specification described  as a shortcut #:), but
yes that is the protocol that is used.
As for your question about the difference between EmbedConnection and
Networked Connection ...

The Networked Connection  is really just a remote handle to an
EmbedConnection. The network client JDBC driver translates JDBC calls
into  protocol sent over TCP/IP  and then Network Server translates that
protocol back into JDBC calls to the  Embedded driver.  The whole system
is  a JDBC -> protocol  -> JDBC converter. So for every client
connection there is a corresponding  EmbedConnection doing the real
work.  Sometimes the JDBC on the server side is  not exactly the client
JDBC call but some equivalent, for example,
DriverManager.getConnection() will become Driver.connect() within
network server.  Sometimes also  network server  uses Derby  internal
intefaces where a straight JDBC call is not available, but generally try
to avoid it.

Some places to do more reading.

Some general info on network server in the user guide at

The client functional spec

The protocol specs
In Volume 1  take a look at  Figure 4-2 Establishing a Connection to a
Remote Database Manager
This shows the protocol flow for creating a connection. You can find
definitions of specific DDM objects referenced there,  e.g.  ACCRDB, in
the DDM manual (Volume 3).

I think the figures in Chapter 4 of volume 1 are a good place to get a
general idea of  the protocol flow without having to do a lot of
translation.     Sorry, don't know of anyone who has tried to translate
this spec into Japanese #:)

I hope I understood the question correctly.
Can you  close  out DERBY-458  and file the code or doc issue if it arises.



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