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Re: Receiving notifications from SQL Server 2000 that data changed

Subject: Re: Receiving notifications from SQL Server 2000 that data changed
From: MobileMan
Date: Thu, 19 Oct 2006 06:08:02 -0700
Newsgroups: microsoft.public.sqlserver.notificationsvcs
Yes, I agree.  The development effort will probably be moderate to heavy.  
What this is really all about is we have a desktop client that needs "live 
data" sent to it.  Allow me to explain ...

We are building an inventory system and the requirements call for the 
Management software to monitor inventory as it's being moved, consumed, and 
replentished.  The user will pick a specific section of a warehouse and be 
able to watch "the numbers" change and people on the warehouse floor move 
inventory around.  

Because of this "live" data requirement we are trying to find the best way 
for the data to notify the client that it has changed.  Of course, the other 
approach that we are trying to avoid is having the client application 
continuously poll the database to see if anything has changed?  Possible on a 
small system, but on a large system this becomes very problematic from a 
performance perspective.

So, this leaves us with the data being smart enough to inform us that it 
changed.  I was reading a book on SQL 05 and found the info on NS .... this 
is perfect in theory ... and now because of you book (thank you very much by 
the way) we see this is possible on SQL 2000 too.

We will have to develop a custom event and channel, though, because 
techniques like e-mail or SMS are simply too slow (not to mention all the 
unneccessary processing overhead that would be required just to update a GUI 
that a number changed).  Frankly, what we're hoping for is something similar 
to .NET Remoting ... the data changed on the SQL box and we send out an event 
to the application.  The application is listening for that event, and updates 
the appropriate item in our GUI upon receipt.  A simple concept, but, as they 
say, "the devil is in the details" I know this will make for an interesting 
implementation.

Just cracked the cover on your book - we're hoping everything we need to 
build this out will be discussed and exampled in your book.  Are there any 
other sources that you would recommend for this information, or does your 
book cover it?

Thanks Joe - we appreicate it your advice and help on this.
-- 
Stay Mobile


"Joe Webb" wrote:

> SQLNS v2.0 can probably handle what you're describing, but I don't
> think it's going necessarily be a trivial development process. You'll
> need to create custom event providers & custom delivery channels. 
> 
> Do you have the option of upgrading to SQL Server 2005? If so, check
> out Query Notifications as a possible solution. I think it's probably
> a better technological fit for what you're trying to accomplish. 
> 
> http://msdn2.microsoft.com/en-us/library/t9x04ed2.aspx
> 
> If you're constrained to SQL Server 2000 and want to pursue the SQLNS
> route, keep posting questions/comment/etc. 
> 
> HTH...
> 
> Joe
> 
> 
> -- 
> Joe Webb
> SQL Server MVP
> http://www.sqlns.com
> 
> 
> ~~~
> Get up to speed quickly with SQLNS
> http://www.amazon.com/exec/obidos/tg/detail/-/0972688811 
> 
> I support PASS, the Professional Association for SQL Server.
> (www.sqlpass.org)
> 
> 
> On Fri, 6 Oct 2006 12:15:02 -0700, MobileMan
> <[email protected]> wrote:
> 
> >Thanks Joe ... this is pretty close to what we're looking for - great 
> >article.  
> >
> >Let me ask you if there's a way to take SQL Server 2000 and have it send out 
> >"notifications" to an application that we would create that simply listens 
> >for these (or "events" in the sense of the word like .NET programatic events 
> >used to indicate something has happened, such as a user clicked a button, a 
> >Form changed size, or a communications channel was closed, as quick 
> >examples)???
> >
> >Instead of each table firing a trgger which adds a row into a "notification 
> >table" for each added/modified/deleted row (as described in the article), 
> >and 
> >then our program "polling" the notification table to determine what happened 
> >... what we're attempting to do is create an application that is smart 
> >enough 
> >to tell us a row of data changed, instead of the application having to poll 
> >the DB.  For performance reasons we're hoping to find a way to stay informed 
> >of database changes, but without polling.  These notifications could be in 
> >the form of e-mails, which was mentioned in the SQL 2005 documentation I 
> >read, but we'd prefer for the notfication to be in the form of an actual 
> >"event" to keep performance at the highest level possible.
> >
> >Perhaps we'd have to create an application that resides of the SQL 2000 box, 
> >that would listen for these notidications or events, then our "listening 
> >applicaiton" could fire real .NET events from the SQL 2000 box to our other 
> >application which is interested in these changes of data????  
> >
> >Forgive my silly ideas - we're just trying to determine how best to 
> >accomplish this.
> >
> >I would love to hear your thoughts about what I've written here.  Again, 
> >thanks for you help with this Joe,
> >
> >Markus Anderson (a.k.a the Moble Man)
> 

From the ADF:
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        <Providers>
                <HostedProvider>
                        <ProviderName>FlightEP</ProviderName>
 <ClassName>FileSystemWatcherProvider</ClassName>
                        <SystemName>%_NSSystem_%</SystemName>
                        <Arguments>
                                <Argument>
                                        <Name>WatchDirectory</Name>
                                        <Value>%_EventsDir_%</Value>
                                </Argument>
                                <Argument>
                                        <Name>SchemaFile</Name>
 <Value>%_BaseDirectoryPath_%\AppDefinition\EventsSchema.xsd</Value>
                                </Argument>
                                <Argument>
                                        <Name>EventClassName</Name>
                                        <Value>FlightEvents</Value>
                                </Argument>
                        </Arguments>
                </HostedProvider>
        </Providers>


HTH....let me know if I've misinterpreted your question.


-- 
Joe Webb
SQL Server MVP
http://www.sqlns.com


~~~
Get up to speed quickly with SQLNS
http://www.amazon.com/exec/obidos/tg/detail/-/0972688811 

I support PASS, the Professional Association for SQL Server.
(www.sqlpass.org)


On Tue, 3 Oct 2006 12:53:30 -0700, "GeoffN" <[email protected]>
wrote:

>When you install the NS Sample "Flight" where does it draw it's data from? I 
>only ask because I cant figure out where the tables "Flight" it keeps 
>querying from exist.
>
>Thanks in advanced 

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