“Open Data Protocol (OData) is an open data access protocol from Microsoft that allows the creation and consumption of query-able and interoperable RESTful APIs in a simple and standard way”.
The protocol enables the Clients to publish and manipulate the resource identified by URIs and defined in a data model using simple HTTP messages.
To put it in simple words, OData is an open source to exchange data over the Internet. Server hosts the data and clients can call this service to retrieve the resources and manipulate them. Servers expose one or more endpoints which are services that refers to the resources. Clients need to know this server side endpoints to call the service to query or manipulate the data. The protocol is HTTP based and designed with RESTful mindset which means it follows the constraints to be called as a RESTful service.
Since the protocol is HTTP based, any programming language with HTTP stack can be used to consume OData services. Existing Client side libraries can be used to transform the JSON or ATOM payloads from the server into objects making programming simple. On the other hand, many libraries exists on the Server side to generate the payloads in ATOM or JSON from the existing data.
It is important to note that both Client side and Server side development can be in completely different programming languages till the time both are able to communicate via HTTP.
Clients consume the service to query and manipulate the data from OData Services and are also called as Consumers of OData Service.
Similarly, Servers that expose the OData services via endpoints are known as Producers of OData services.
