where to use web services

Question

I am discovering webservices to impliment in my asp.net website. I visited many sites about Why use webservices and read many articles and found out that web services are good when you have something that is used frequently without loading your page.

I want to know some other example scenarios where web services are used. Whether i can use web services in sending an order form to database or it is just for textbox box auto completion like google and etc.

Note: I know web services can be used from mobile, web or desktop applications. But My question is
When do i use web service in ASP.Net Application?

Some articles read so far

• Codeplex
• How to create a Web service using Visual Studio.net
• w3school

Answer 1

Web Services are the means by which devices communicate over the World Wide Web.

Whether you use a mobile application, search engine or an enterprise system, the user piece of the application (the interface) resides on your device.

The data, and potentially the business rules, live on some other server on the network. How your interface communicates with the server piece is the role of Web Services.

Answer 2

On a Large Scale, Webservices are basically written, when you want to expose your database, your code, to some other user.

By exposing database, means, suppose, you have a large collection of all the pharmaceutical companies in a given region, storing details in db like, medicines they produce, their policies etc etc. And now, you want people to use it(possibly your paid Client, or simply free access to anyone). So what you going to do? Obviously broadcasting working connectionString to your database will be a disastrous move.

So what you do is to make few methods on top of your db i.e. CRUDE operations and expose these methods in your WebService i.e. someone can interact with these methods through a URL and fetch data or send data or both.

Most general use of WebServices is when you want your specific language built( say ASP.NET) logic and data to be accessible to people on different platforms.

Like mobile devices. Their frontEnd is built in fancy framework say like Titanium, but they fetch their data through a Sql Server using WebService built with Microsoft's WCF-Rest approach. They store their data, Synch their data through a WebService.

In a typical example, We had a very large shopping Website, and it was standalone i.e. we were the only users of its database, its data, its users. But then a requirement came, that certain Client wants to model it and make use of its existing data and logic, but they have got JAVA platform. Our entire system was built on ASP.NET 3.5. What to do then. We simply exposed our BAL through a ServiceLayer and gave it a fancy name ServiceBAL and lived (and earned) happily ever after.

These are some business oriented usage of Web Services.

Other simple, mere usage of webService like textBox auto completion, existing user check and so many, am sure, you must have found out during your scout.

Answer 3

Web services are reusable components you can use anywhere. for example suppose you are building order processing system where order can be place by mobile,web etc. So instead of creating a different function for different application or different platform it's better to create a web service of order processing system such as placeOrder or takeOrder web service and consume them on different applications.