In a prior post

http://forum.strataframe.net/Topic5041-6-1.aspx?Highlight=Notification

You mentioned that you support SQL 2005 Notification Services.   Is this a native BO function or just based on the fact that SQL Server 2005 Ntification Services produces SQL?    I was looking for the samples or section in the help and did not find anything.

Thanks,

Richard

It is native, but the Broker Server MUST be turned on on the database and you have to tell the BO to register with Notification services in order to .  If you use the DDT, it will turn the broker service on for you if you check the "Enable Broker Server on Database" with the database properties.

Also, you have to set the ReceiveQueryNotifications on the BO to True.  Then you will be able to use the notification services.

Ahhh,  I just started looking at the DDT and saw that checkbox.   Man you guys are fast.

Thanks,

Richard

Well, we try

Just FYI....I thought I would add that you may want to use this sparingly.  By turning on a broker service you are increasing the amount of resources required for the database to respond.  Also, if you register too many notifications, you will also impact the performance of the database. 

Took 5 minutes to build a BO and map these properties.  Wow...   Makes so many parts of an application Asynchronous when you don't need to keep populating.  

Anyone build a Lookup Object Service that registers BO's into a Collection and then you can share then across other forms?  Obviously you don't want to instatiate all lookups until you need the first one, but something that creates a Business Object for Payment Terms which is used for a lookup on Sales Orders, Customers, Invoices would be really cool especially tied into the Notification Query.     There are probably a few dozen lookup objects for any application, like this.    You could create a timeout propety as well to dispose of a Lookup BO after a certain duration to free up memory.

The more I use Strataframe the better I like the power and flexibility.

Richard

Hi,

What are the common usage of notification service, auto requery BO populated combobox/list if any update at database?

Thank you

Yes, the most common use for Query Notification Services is for requerying lookup data and such and to avoid concurrency issues.  Say you have created an appointment scheduling program... if two people side-by-side are creating appointments, then you would want the changes by one user to be reflected on the other user's screen, either by polling the server for changes or by registering a query notification. 

Any idea how the 3-Tier Server handles objects with Query Notification Services turned on?  I haven't explored the 3-tier option yet and wonder if this option will have design implications regarding the Query Notification usage.

Richard

Query notification services are more than likley never going to work in a 3-tier environment.  The reason is because there is not a persistent connection between the tiers, which is a good thing.  You can understand more about why we do not maintain a persistent connection by looking at the Smart-Client ES pages on the web site.  In order for query notifications to work there must be a persistent connection to the database which is listening for an event.