What is OData?
OData (known as Open Data Protocal) is a web protocal for querying and updating data. It is used to expose and access information from a variety of sources like relational databases, file systems, web sites etc.
What are WCF Data Services?
WCF Data Services are used to expose and consume data via web services accessed over HTTP.
How do you access WCF Data Services?
WCF Data Services uses the OData protocol for addressing and updating resources. So, these services can be accessed from any client that supports OData. OData enables requesting and writing data to resources using Atom(a set of standards for exchanging and updating data as XML) and JSON(a text-based data exchange format).