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From David Van Couvering <David.Vancouver...@Sun.COM>
Subject Re: [jira] Commented: (DERBY-458) Make it clear the difference between EmbedConnection and Networked Connection
Date Mon, 22 Aug 2005 20:55:09 GMT
Is it worth considering finding some way for the embedded and client 
drivers to share some code, so that the only real difference is that the 
network one is sending its commands over the wire?  This again broaches 
the topic of veering away from DRDA...


Kathey Marsden wrote:

>TomohitoNakayama wrote:
>>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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