Web services + design question

nialo

Hi all,

Have a problem at the moment with a new project i have started. System is a filing management application. Back end sql server 2005. Database design mostly done at this moment in time. the system is to be delivered over the web via hand held devices (windows mobile application) and pcs (asp.net). Both have uses. Pcs will be for searching and admin work. hand helds will be for check in and out files and dealing with requests and sign off on file acceptance.

My problem is that im trying to implement a layer where all database access is via web services to ensure compatibility across display methods. No real experience with web services so not sure if i should be implementing a single web service with each method returning datasets when dealing with objects over primitive types? or creating a class for say a File object and passing back arrays of these objects?

What would be the correct or preferred way of implementing this keeping in mind caching and response times.


Any help or comments welcome.

Cheers

N.

Evil Phil

If all you consumers are going to be .Net than I would go with datasets, if they're not .Net then you may have to parse the XML returned with each dataset yourself which could be a headache.

Ginger

As Phil said, use Datasets for all your returns.

From there you can pass that datasets and put them into your business objects. Your datalayer should just deal in datasets not complex types.

With your WS, just have 1 web service and different method calls. You can always overload them if need be. That way its just 1 reference that needs to be updated to have all your data access

You can implement caching on your web service as well, if you so need. For DB access look at connection pooling and MARS if you are using SQL 2005. You can also use HTTP endpoints if you so desire, but thats another thing.

stevenmu

Like the others said, use datasets instead of complex types. And IMHO it's fine to use primitive types in many cases aswell, for e.g. if you want to get the status of a file, just pass back the status id, not a whole dataset containing the whole file row.

And try to just use a single web service. Remember your web service class can be just an interface to the functionality, each method can draw on functionality in other classes

nialo

Cheers for the replies. was talking to a few ppl and data transfer object were mentioned as the preferred way of returning objects as appose to coding datasets..

for the moment it looks like this application is purely .net based so think ill go with the datasets cause its easier!

Thanks for the advice..

N.

Ginger

Download the Web Services software factory and the Enterprise Application blocks..

They will shorten your development time

Evil Phil

^^ what Ginger said.

stevenmu

And consider the web client software factory for your ASP.Net interface, I've been using it a bit lately and it's pretty cool.

I'm not sure but I believe there's a mobile client software factory too. Could be worth looking into.

nialo

Ya im currently using the enterprise application block for the current framework we have. but will look into the others.

Ginger

There is a Smart Client one as well as the Web Apps one

http://msdn2.microsoft.com/en-ie/practices/default(en-us).aspx