This is what I was talking about (I think): http://msdn.microsoft.com/en-us/library/ms172133.aspx
Personally I'd probably just poll unless my demand load suggested notifications would work better. Paul From: ozdotnet-boun...@ozdotnet.com [mailto:ozdotnet-boun...@ozdotnet.com] On Behalf Of Paul Stovell Sent: Tuesday, 29 March 2011 11:45 PM To: ozDotNet Subject: RE: Propagate Database changes to application Correct, though once upon a time I did have an experiment that worked with query notifications. From memory you attach some kind of SqlDependency object to your SqlCommand (not the type that works with triggers - it used the same code as clustered views from memory). There is a trade off either way you go. With a notification system you can end up "drinking from a fire hose" if the events happen too frequently under load (e.g., an Orders table probably isn't good for notifications). Systems that rely on polling tend to scale better (for example: this little thing called the internet) but that's a generalization. Out of curiosity, is this something that needs to happen at the database level? Should more than one process really be writing to the database at once? Could it be done using a messaging system above the database? Paul From: ozdotnet-boun...@ozdotnet.com [mailto:ozdotnet-boun...@ozdotnet.com] On Behalf Of Grant Molloy Sent: Tuesday, 29 March 2011 9:32 PM To: ozDotNet Subject: Re: Propagate Database changes to application Ok.. well it looks like bindable linq only propagates changes from what it's got in memory already, not from changes in the database.. On Tue, Mar 29, 2011 at 9:26 PM, Grant Molloy <graken...@gmail.com<mailto:graken...@gmail.com>> wrote: Hi Joseph, I wasn't really looking at any particular single client solution.. If Paul Stovell is listening, what did you use in Bindable Linq.. I am downloading now to have a look, but thought you may be able to put into words for larger audience.. thanks On Tue, Mar 29, 2011 at 9:59 AM, Joseph Cooney <joseph.coo...@gmail.com<mailto:joseph.coo...@gmail.com>> wrote: Re: client type - I was more wondering is it a web app? Windows app? Silverlight? Windows intranet app could do udp broadcast of changes from the server or something like that. Sent from my iPhone On 29/03/2011, at 8:18 AM, Grant Molloy <graken...@gmail.com<mailto:graken...@gmail.com>> wrote: Thanks everyone for feedback.. Joseph, SQL Server, yes, version either 2008 or 2008 R2.. More than likely R2, but not nailed down yet. Client type is a DAL DLL.. I want the DAL to know when the data changes, and the client will subscribe to DAL events, and then DAL can fire off event when data is changed, and App can decide what to do about it. Kind of like a publisher / subscriber model implementation. I'm not 100% sure I'm going about it the right way or have the events in the right place (ie in the DAL).. On Tue, Mar 29, 2011 at 1:55 AM, Joseph Cooney <joseph.coo...@gmail.com<mailto:joseph.coo...@gmail.com>> wrote: What type of client is it? Do you control the means by which data is written to the table? Are clients deployed to the internet or intranet? What kind of database are we talking about here (I assume you mean SQL Server, since you mention SqlDependency) but which version? Joseph On Mon, Mar 28, 2011 at 8:33 AM, Grant Molloy <graken...@gmail.com<mailto:graken...@gmail.com>> wrote: Hi list, I'm looking to have an application automagically update it's view of the data when the data in the connected database table changes. I've seen two main ways to do this so far. 1. Poll the database every n seconds 2. Use the System.Web.Caching.SqlDependancy object. Does anyone else know of any other better or smarter way of doing this ? thanks Grant -- w: http://jcooney.net t: @josephcooney
