It’s not uncommon for businesses to have tremendous amounts of data locked behind application interfaces that are designed to query and modify.  But what happens when a business wants to expose the data to the world and let everyone query it?  Well, you have to unify the storage type and enable technology that can query the data in a well-known and uniform way.

Using HTTP, Atom Publishing Protocol (AtomPub), or JSON will allow you to query information from a variety of applications, services, and stores.  From there, the next step is to convert your data into a well-known format with an API that any technology can use.

Transforming your data into an Atom feed and using The Open Data Protocol (OData) will do the trick.  This protocol emerged from experiences implementing AtomPub clients and servers in a variety of products over the past several years.  OData can be used to expose and access information from a range of sources including, but not limited to, relational databases, file systems, content management systems, and traditional web sites.

For Sample OData Service see: http://services.odata.org/Northwind/Northwind.svc/.  This will simply display the entities’ names in the storage.  By adding the entity name to the query URL: http://services.odata.org/Northwind/Northwind.svc/Employees, you will be able to see an AtomPub feed.  Then, to query by employee id, for example, you can easily add your custom filter to the data: http://services.odata.org/Northwind/Northwind.svc/Employees()?$filter=FirstName eq ‘Davolio’.  This method of filtering data is amazing and very easy to do.

You can use several tools to get more familiar with the OData.  For example LINQPad is a tool for building OData queries interactively.

For more information on the OData producers see: http://www.odata.org/producers.  For more information about OData consumers see: http://www.odata.org/consumers.  And if you want to develop over OData SDK see: http://www.odata.org/developers.

For a ready OData service you can use experiment with directly see below: