Alex Barnett blog


Why OData Matters (IMHO)

Earlier this week I was in the MIX10 crowd as Douglas Purdy announced the Open Data Protocol (it was a great presentation - summarized here).

I want to share with you why I think OData could be a very big deal…But before we go there...let's start with the basics...

What is OData? Where Did OData Come From?

To understand the history of how OData came to be, you need to understand how project "Astoria" came to be...I won't go over that again as this is already pretty well documented. Astoria OData has come a long way since.

In a nutshell: Today, OData builds on a few conventions, popularized by AtomPub (see OData AtomPub Format), to using REST-based data services. These services allow resources, identified using Uniform Resource Identifiers (URIs) and defined in an abstract data model (see OData URI Conventions, to be read and edited by web clients using simple HTTP messages (see OData Operations).

An Open Data Protocol for the Web

OData offers a standardized way for programmable data to be made available across the web and in turn allowing "consumers" of that data to rely on a set of conventions to be followed that in turn allows many interesting things to happen if widely adopted...

...And to this end:

  • As announced, OData has been released by Microsoft under the Open Specification Promise (OSP) "to allow anyone to freely interoperate with OData implementations" . Since then, the W3C has invited the OData team to Bring OData to a W3C Incubator (I haven't seen a public response yet but I urge the team to do so.).
  • OData is not a Microsoft-only thing and it won’t succeed if it is. The originating philosophy was about transparency in the design process, with an Open end-point as the goal - not a .NET lock-in play (“agree on standards and compete on implementation”). This approach has already yielded an initial set of clients, servers, services, and tools. Today, a number of OData SDKs and libraries are available for .NET, Java, PHP, iPhone (Objective-C) and more – and there’ll be more coming.
  • There is a small but growing ecosystem of non-Microsoft "producers" and "consumers" - (where  OData "producers" include Netflix’s catalog as OData and the VanGuide (a social map of Vancouver Open Data) and Public data from the city of Edmonton as OData) and OData “consumers”  - standard web browsers, RIA "data explorers" – such as Sesame OData Browser, and the client libraries mentioned above – p.s. somebody build a javascript-only data browser please!)

Where can OData take us?

The clue is in the OData icon (next to the RSS feed icon. Can you see the similarities?

odata icon rss icon

The big idea here is that in the same way we have the "RSS" feed icon, we'll get used to seeing the "OData" icon on commercial and non-commercial websites everywhere (especially for government-related data). So in the same way you know today that the RSS icon means "get an XML feed for this content", the "OData" icon means "get this web data" - you'll know (and your client will know) what to expect in terms of how to read in, and navigate through and query structured web data sets - and in many cases write against them - using a common syntax.

Q: Right, But So What?

A1: Open Government OData. From Open Government Data Principles

The Internet is the public space of the modern world, and through it governments now have the opportunity to better understand the needs of their citizens and citizens may participate more fully in their government. Information becomes more valuable as it is shared, less valuable as it is hoarded. Open data promotes increased civil discourse, improved public welfare, and a more efficient use of public resources.

That’s great, but it needs to be practicable…And number 5 of the 8 Principles of Open Government Data sensibly states that the data should be (via David Eaves):

5. Machine processable

Data is reasonably structured to allow automated processing.

It'll be down to each government agency (and local government) as to how they decide to implement this principle, but wouldn't it be great if they agreed to a standard (and a powerfully simple, web-oriented one at that)? This is what Jon Udell concluded here:

"The open data movement, in government and elsewhere, aims to help people engage with and participate in processes represented by the data. When you publish data in a fully articulated way, you build a framework for engagement, a trellis for participation. This is a huge opportunity, and it’s what most excites me about OData"

A2: To ODatarize your data is to RESTify your data.

As more data-oriented web APIs come online, each team responsible for the design of each web API is confronted by the same kinds of questions, and each team answers these in their own particular way. Increasingly, “RESTful” is a design goal of web APIs. Great…but what does that mean? How do you expose the data, the relationships between the entities inside the model, and what should the querying syntax look like? Unfortunately, there are as many answers to these questions as there are RESTful web APIs. And there needn’t be.

For to ODatarize your data is to RESTify your data. Do spend the time at the value layer - figure out the way your developers / consumers want to see the data and expose it that way. Do make it easy for devs / consumers to learn / navigate about the data and use it. Do not make them learn about the unique idiosyncrasies you’ve built into your API (or those that leak out of your originating store) :-)

From a developer’s standpoint, OData is ultimately about  productivity.

  • For the OData “Production Developer”: Point at your data store – define your entity model and map it to the data model you already have (so your developers consume / program against the data that makes most sense to them – effectively ORM’ing) and expose as an OData service, inheriting: all the REST characteristics; entity relationship self-discovery; and querying goodness.
  • For the OData “Consuming Developer”: If you know the web API is OData…great! Pick up a client library, get to the API end-point ( Point and Shoot: Traverse the data model, query it (and bookmark as needed – it’s a URI)…play!

(see links at the bottom of this post to technical content that provides details on all this)

A3: Since the announcement, I’ve seen quite a bit of excitement around the web (especially Twitter) by developers who see the potential here…there is plenty of experimentation going on. At Intuit, my team is also experimenting with ODatarizing some of our data services, exploring how it might be applied across a number of our cloud based data services. And when our team’s architect Tweets that “Looks like #odata is going to be a good fit for our data services”, I know there’s something interesting going on here…

So I encourage you to find out more about OData and get involved.

More Resources


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# April 2, 2010 3:10 AM