strongly typed datasets adapters

Question

hi everybody i have just started to use strongly typed datasets (which seems to me as a wonderful tool) and i saw there are correspond adapters for every strongly typed table but i could not understand how to use those adapters for reading not all the table's rows but part of them by some query... thanks a lot:)

Ashley Argile · Answer

Are you refering to the data adapter that get created when you add tables to your dataset they appear at the bottom of the table in the design view. Well if you right click the adapter name in that view there's an option to configure and from there you can modify the select statement or even use stored procedures if you want. When you've finished the Fill method on the adapter instance will be updated to take whatever parameters you specified in your query. Personally I prefer to add my own data adapters as they seem to be more flexible. Regards Ashley

Ashley Argile · Answer

Itay Business and Enterprise software is frequently based on a tiered architecture. This normlly consists of a Data Access Layer that communicates with your Database a Business Logic layer that implements processing specific to the business and finally a Presentation layer that implements the UI. i.e. So an interaction with the UI could result in calls moving down through all of the layers. Presentation Layer -> Business Logic -> Data Access Layer -> Database. These layers do not necessarily have to be implemented on the same physical machine. The presentation layer could even be a web app running in your browser (It doesn't have to be a web app though). And here's another article which might help explain things (this one is a ASP.NET application but it could equally be a WinForms app).... As for strongly typed datasets in business software the application I work on uses them quite successfully although a good alternative is to create data objects using NHibernate. I don't know much about NHibernate at the moment but my company is looking at it as an alternative to datasets. Strongly Typed datasets are definitely worth knowing though! Regards Ashley

Itay · Answer

That is good enough for me:) what exactly is that data access layer? does it refer to datasets etc.? and one more question... do you whether or not it is customary to use strongly typed datasets in business? thanks a lot again

Ashley Argile · Answer

If you create the data adapter in code then yes you're going to have to setup the connection string etc manually. What I meant was to add a SqlDataAdapter component to your form from the toolbox (you might need to add it to the toolbox. I don't that it's a default). You still get wizard support like you did when you configured the adapter attached to the table but you get access to the commands in code afterwards. You can also map the output of the adapter to many tables in your typed dataset something that I'm not sure you can do in the auto generated ones. It depends what you're trying to do really if the auto generated ones work for you then use them. In the work I do we tend to have one adapter per stored procedure and they all live in a component in the applications data access layer. The underlying stored procedures can be pulling data in from many tables and the data adapter needs to be flexible enough to cope with that. Regards Ashley p.s. I'm no expert on this stuff. I just use them everyday.

Itay · Answer

thanks a lot really :) but with pure SqlDataAdapter you must rewrite the connection string and all that stuff every time don't you?