-> SAP Gateway is a development framework available with SAP Net-weaver.
-> SAP Gateway is a technology that provides a simple way of establishing connection between SAP System and target clients, platforms and programming framework.
-> SAP gateway provides easier consumption of business logic and content of SAP system for web and mobile applications.
-> Its a framework that connects business users to SAP system using mobile devices and others and is based on open standards(oDATA) that offer simple services based on REST principle.
What is REST? It stands for: Representational State Transfer
It is a software architecture for distributed systems such as WWW(World Wide Web).
Let’s take the case of Client and Server interaction with request and response mechanism.
->Client sends a request for some resource information ( all employee details) to the server.
-> In the Server, the request processed where it retrieves all employee information from DB and sends this resource information back to the client in some representational form.
A better example to understand the word of representational would be, the client request for a flower on internet and this flower is actually stored as binary format but when it reaches back to the client, its format is IMAGE( some representational form).
So with REST, the response (for the requested resource) can be received in XML, HTML, JSON or some other format which can be consumed by tech rich web applications.
With REST, the communication is faster(stateless protocol) and much more reliable.
HTTP is a REST based stateless protocol that supports predefined CRUD HTTP methods GET,POST,PUT,DELETE and others.
oDATA: stands for Open Data Protocol
Its an open web protocol for querying and updating data. With this protocol, a query for the data source can be made over HTTP protocol and the result can be obtained like JSON, XML and etc. In addition to this, with oDATA, it is possible to have filtering of data, ordering and pagination.