Technical advice needed regarding polling the database

[forkirun]

I have a database which is very frequently updated .I want an option that user can specify that after how many minutes he/she wants to see those changes . Like a mechanism which would do

1. Poll database after a user defined period and then bring those changes ,mean while displaying the stale data (like Cache )
2. Also allow user to choose if he/she wants to see/notify updates as they come
3. Can notify change ( if any ) in a particular table occur

I have read a lot about SQLDependency class which is used to data caching .The reason I am confused is

1. The recommendations are that don’t use this feature if your data is frequently updating (in my case data is frequently updating)
2. The class does Cache data for me but I cant find any mechanism which would notify me that a change has occurred and how many row in a particular table are added.

I am confused .What feature I should used . Should SQLDependency class can do the things I want or these can be done without SQLDependency Cache feature .

Please advice.

[Igor Soukhov]

I think we could all use little more information of the system you're developing before giving out any advices.

But even now I have something to say:

*That you call "giving user a option to specify poll frequency" I call "shift the burden to the user" because normally users don't think in terms of "database update" and it's not user friendly after all.

*The reason why MS doesn't not recommend using SQLDependency on frequently updated data - is performance. Magic comes with a high price - every time you create SQLDependency object MSSQL Server 2005 creates a queue and notification service in database.

Post more information about design and architecture of your project,
about static structure of database, how data is changed/added, etc and
we'll start it from there.

I have a database which is very frequently updated .I want an option that user can specify that after how many minutes he/she wants to see those changes . Like a mechanism which would do

1. Poll database after a user defined period and then bring those changes ,mean while displaying the stale data (like Cache )
2. Also allow user to choose if he/she wants to see/notify updates as they come
3. Can notify change ( if any ) in a particular table occur

I have read a lot about SQLDependency class which is used to data caching .The reason I am confused is

1. The recommendations are that don’t use this feature if your data is frequently updating (in my case data is frequently updating)
2. The class does Cache data for me but I cant find any mechanism which would notify me that a change has occurred and how many row in a particular table are added.

I am confused .What feature I should used . Should SQLDependency class can do the things I want or these can be done without SQLDependency Cache feature .

Please advice.

[TheCPUWizard]

If you are using SQL-2005, then consider using the event model instead of polling.