Developing with SAP Extension Suite

Describing OData

Objectives
After completing this lesson, you will be able to:

After completing this lesson, you will be able to:

  • Describe the OData standard for web-based applications

What is OData?

Usage Scenario

Your company is planning to develop a set of web-based applications. Open Data Protocol (OData) is intended to be used for data access as a standardized access protocol that meets the requirements of modern Web development.

Overview

The OData is a data access protocol built on core protocols like HTTP and commonly accepted methodologies like REST (Representational State Transfer) for the web. Thus, as common practices of REST, OData builds on HTTP, AtomPub, and JSON using URIs to address and access data feed resources.

Key Challenges in Enterprise Computing for Business Consumers

Watch this video to discover the key challenges in enterprise computing for business consumers and the solution.

OData Service

OData currently supports two formats for representing the resources it exposes - the XML-based AtomPub and the JSON formats. JSON has significantly less protocol overhead than the Atom Publishing protocol. JSON can easily be consumed with Java Script and by SAPUI5.

Each OData service is represented by a URI, called the service root URI. A URI is a uniform resource identifier, which is a string of characters used to identify a resource. More precisely, each resource can be accessed using a URL, a uniform resource locator, describing how to access the resource. This type of identification enables interaction with representations of the resource across a network using specific protocols like OData.

There are two types of document associated with each OData service:

  • The service document
  • The service metadata document

The service document lists entity sets, functions, and singletons that can be retrieved. Clients can use the service document to navigate the model in a hypermedia-driven fashion. The service document is available at http://<host>:<port>/<service>/.

The metadata document describes the types, sets, functions, and actions understood by the OData service. Clients can use the metadata document to understand how to query and interact with entities in the service. The service metadata document is available at http://<host>:<port>/<service>/$metadata. The URL will return XML metadata of the service (Entity data model). The response of a service metadata document only supports XML.

CRUD Operations

OData API

An Application Programming Interface (API) allows you to access data, for example, monitoring data.

The OData API is implemented as a REST API and the technical protocol is OData. This means that you can use standard HTTP methods (for example, the GET method) to call the API.

Summary

You now have a more profound understanding of the OData protocol and why it is so useful in modern web development.

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