dhRichClient transactions

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Phil McFarlane - 10 Mar 2010 23:34 GMT

With my current project I need to do a series of
db updates to different tables within a
transaction on a rpcConnection. I have tried to
work out how this can be done but have made no
progress.

Any help or examples would be appreciated.

phil_mac

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Schmidt - 11 Mar 2010 10:28 GMT

> With my current project I need to do a series of
> db updates to different tables within a
[quoted text clipped - 3 lines]
>
> Any help or examples would be appreciated.

You will need to do this at the serverside, since
the communication with the DB over the dhRPC-
functions is really "connectionless" (of course you
have socket-connections - but what I mean is,
that there is no permanent DB-connection to a
'DB-cConnection-Object' at the clientside).

So, please transfer everything you need (some
serialized cRecordsets - or "Raw-Data" in some
format of your choice (a CSV-String or your own
"String-Format", or XML - or a serialized cCollection)
to the serverside over a new written Function - and
then process the transaction within the code of this
new serverside Method.

And BTW, the SQLite-engine has (since one year or so)
nested transaction-support built in, in case you need that...

Regards,

Olaf

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Phil McFarlane - 11 Mar 2010 11:42 GMT

Olaf

I understand (I think)from your reply that I will
need to move my record sets to the server and
complete a transaction on the server. How to do
this is my problem. My previous experience with
DAO and Access is of no help and I am unsure how
to proceed. If you know of any examples that would
help they would be appreciated.

Thanks

Phil

>> With my current project I need to do a series of
>> db updates to different tables within a
[quoted text clipped - 25 lines]
>
> Olaf

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Schmidt - 11 Mar 2010 18:57 GMT

> I understand (I think)from your reply that I will
> need to move my record sets to the server and
[quoted text clipped - 3 lines]
> to proceed. If you know of any examples that would
> help they would be appreciated.

In Oct. 2009 we had a short discussion about recompiling
the small DBServer.dll which hosts the basic-functionality"
for Remote SQLite-communication (containing only a few small
functions in one single, serverside Class cDBAccess.cls).
This thread also contained a suggestion, to switch-on the
dhRPC-DebugMode for your further (much more easy)
enhancements on the function-set within that DBServer.dll ...

Here's the thread again:
http://groups.google.de/group/microsoft.public.vb.database/browse_thread/thread/
59f397e6bb7b58e0/2a899212d662a15c

So it would be great, if you could try to make the appropriate
efforts, to manage your first "fully debuggable Server-Code-
Rountdtrip" against the DBServer.dll-*Project* again.
Maybe starting with one of the smaller Functions which are
already built in (e.g. Step-By-Step debugging of the retrieval
of a simple, small Recordset from the serverside DB).

If you are beginning to "feel familiar" with that Debug-Mode
again, we should talk about new serverside Functions
(Methods) within the cDBAccess-Class of DBServer.dll.

Just ask, if you have more questions with regards to these
Debugging-preparations ... if you have it running, you
could already try, to implement something very simple
yourself - as for example in the cDBAccess.cls:

Public Function Reflect(S As String) As String
Reflect = StrReverse(S)
End Function

Then add the necessary clientside "wrapper-call" into
your Main-Exes Private Class, which is responsible
for the RPC-Calls - and try to use this new call
from your GUI - start in Debug-Mode first - and then
maybe also in "compiled mode", by placing the
recompiled Dll again in your Server-Directory.

If you managed, to "successfully reflect strings" ;-),
(your "Debug-Recompile-Test-workflow") again
refreshed in your mind, then adding a Public Function
which handles serverside DB-transactions should be
no larger problem anymore...

Olaf

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VB Forum / Database Access / March 2010

dhRichClient transactions