VPN connected sql servers

[Steve]

Hi All

I have an appointment based application (Windows forms vb.net 2008) which in
the case of 1 customer is running at 3 different physical locations

They are connected via a secure VPN

Any 1 store can bring up the appointment screen for any other store and make
appointments etc

I currently use a windows.forms.timer to refresh the appointment screen
every 10 secs to ensure the appointment screens at each location display the
current data

I am sure there is a better way to determine when an appointment screen
refresh is needed at a particular location

What is the industry standard for doing this....

1. Should I set a flag or timestamp in the remote database when an
appointment has been added from another location and check that flag within
a timer before calling a refresh?

2. Or is there a better way


Regards
Steve

 

[Zhi-Xin Ye [MSFT]]

Hello Steve,

As I understand, you have three application clients running on three
different physical locations, they're use the same SQL Server database.
When one client update the data in the database, you want the other two
clients to display the new data.

Before we go any further, would you please tell me which SQL Server version
do you use?

Anyway, you can try the Query Notifications in SQL Server, it is used for
applications that need to refresh displays or caches in response to changes
in underlying data. For more information about Query Notifications, you can
refer to these documents:

Query Notifications in SQL Server (ADO.NET)
http://msdn.microsoft.com/en-us/library/t9x04ed2.aspx

Working with Query Notifications
http://msdn.microsoft.com/en-us/library/ms130764.aspx

Using Query Notifications in .NET 2.0 to handle ad-hoc data refreshes
http://www.codeproject.com/KB/database/QueryNotifications.aspx

If you have any questions or concerns, please feel free to let me know.

Sincerely,
Zhi-Xin Ye
Microsoft Managed Newsgroup Support Team

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[Steve]

Hi Zhi-Xin

Thanks for the reply

Sorry for leaving the SQL Server version out of the post, I am using SQL
Server 2005 Express

You are correct I have a client running my application at 3 different
physical locations

Each location is stand alone in that they have their own SQL Server express
instance and data

However within my application, Location A can bring up the appointment
screen for any other location e.g Location B, and make, edit or delete an
appointment at Location B

Location B needs to have their appointment screen refreshed so they can see
the changes made to their appointments by Location A

As this doesn't happen regularly, I don't just want to call a refresh from a
windows forms timer every 10 seconds or so, but only refresh when there is
evidence the appointments have changed

Regards
Steve