OpenLink Data Explorer Extension

What is the OpenLink Data Explorer Extension?
- Why is the OpenLink Data Explorer Extension Important?
- Product Architecture
What is Linked Data?
- Why is Linked Data Important?
- How Does Linked Data Work?
What is the Linked Data Web?
- What is the Linked Data Cloud?
- Why is the Linked Data Web Important?
How can the OpenLink Data Explorer Extension help me exploit the Linked Data Web?
- Download
- Installation
- Configuration
- Use
- Examples

What is the OpenLink Data Explorer Extension?

The OpenLink Data Explorer is a browser extension (currently available for Firefox with additional browser support to follow) that adds a new option to the Web User Agent functionality realm in the form of new main and context menu options for viewing Data Sources associated with Web Pages.

Why is the OpenLink Data Explorer Extension Important?

It allows Web users to explore the raw data and data relationships that underly a Web page. The extension enables users to switch between Hypertext and Hyperdata link traversal of Web data.

Product Architecture

ODE uses a modular architecture to orchestrate component activities according to the M-V-C pattern. Orchestrated components, referred to as "Cartridges," deliver functionality comprising data extraction and modelling (Model), data display and presentation (View), and actions based upon and/or guided by that data (Controller). Each component is independent of the others, and all are coupled with ODE via HTTP messaging.

OpenLink Data Explorer Architecture graphic

What is Linked Data?

The term "Linked Data", coined by Tim Berners-Lee in a 2006 Design Issue note, describes an entity level "Data Access by Reference" mechanism for the Web, courtesy of dereferenceable URIs.

Why is Linked Data Important?

It provides direct access to the raw data entities within (or behind) Web pages; thereby enabling the construction of powerful "data meshups" across heterogeneous data source collections, without any programming.

How Does Linked Data Work?

By incorporating HTTP into the resource naming schemes of Web accessible resources, so that the same linking mechanism used for retrieving a Web Page (and other information resources) also extends to the process of retrieving a structured description of a resource. This process is quite similar to accessing a SQL recordset via an ODBC or JDBC data source name (DSN). The fundamental differences between Linked Data and SQL CLI based data access are:

Linked Data URIs name / identify individual records while SQL data access DSNs are scoped to record containers such as Database, Table, View, or Stored Procedure names
Linked Data URIs facilitate untethered data access that transcends database vendor, database engine, operating system, programming language, application server, application development framework, and other infrastructural confines, unlike ODBC, JDBC, and other data access mechanisms.

The illustration below highlights Linked Data's parallels with ODBC in relation to DSN based data access.

Linked Data and Open DataBase Connectivity are worked in the same fashion

What is the Linked Data Web?

An evolution of the Web that places you a click away from a structured description of any Web accessible resource. A more granular Web where interaction focus moves away from opaque compound documents to the entities they host.

What is the Linked Data Cloud?

As illustrated below, it's the moniker for the growing collection of Linked Data sources being injected into the Web by the Linking Open Data Community. As Kingsley Idehen stated in his recent blog post, "Semantic Web: Travails to Harmony Illustrated", harmonious intersections of instance data, data dictionaries (schemas, ontologies, rules etc.) provide a powerful substrate (smart data) for the development and deployment of "People" and/or "Machine" oriented solutions.

The clickable venn diagram below provides a simple exploration path that exposes the linkage that already exists, across the different Linked Data types, within the burgeoning Linked Data Web.

There are several paths to materialized Linked Data.

"On the fly" generation via RDF middleware, from
- Annotated Web Documents (e.g., Semantic HTML)
- Web 2.0 Data Spaces
- Web Services
(click for full-size, clickable image)
Enterprise Data Sources, such as:
- SOA Web Services
- XML -based Data Warehouses and Views
- Enterprise Databases
Community Driven Extraction Efforts, such as:
- DBpedia
  
  (click for full-size, clickable image)
- Bio2RDF
  
  (click for full-size image)
- and others in the LOD Cloud

Why is the Linked Data Web Important?

By providing bridges between areas of interest and knowledge, the Linked Data Web can reveal relationships where information might otherwise be seen as unrelated. For instance, one might explore which industry and government leaders had previously been classmates or were somehow connected by family.

The OpenLink Data Explorer enables a user to browse from one "thing" to another just as easily as they would click from one page to another with standard hyperlinked document browsing, but with greater understanding and comprehension from the first click.

How can the OpenLink Data Explorer Extension help me exploit the Linked Data Web?

The best way to learn how this extension can help you is to install it, and follow along with the examples below. If you decide you can't benefit by exploiting the Linked Data Web in this way, you can un-install the extension without harm.

Download

The OpenLink Data Explorer can be downloaded from one of the following locations

Installation

The loading of the OpenLink Data Explorer tool differs slightly depending on which method was using to download it.

From the Mozilla Add-ons site, click on "Add to Firefox", Firefox will then install the Extension as an "Add-on".
From the OpenLink Web Site, download the "ode.xpi" file and load from the "Open File" menu item of the Firefox "File" menu.
From the Amazon S3 Storage Site, you will immediately be presented with the option to install the ODE add-on.
From the Softpedia Web Site, download the "ode.xpi" file and load from the "Open File" menu item of the Firefox "File" menu.

The OpenLink Data Explorer Firefox Add-ons installation dialog will then be presented.

You will need to restart Firefox after it has finished installing.

Restart Firefox after installing the Add-On

Once it has finished restarting, you should see the extension in your add-ons list.

Configuration

To reach the preferences panel for the OpenLink Data Explorer Extension. Go to the "Tools" menu and Click on "Add-ons". Then select "OpenLink Data Explorer" and click on the "Preferences" button.

There are two tabs for configuration:

The "Viewers" tab
The "RDF Data Access" tab

The Viewers Tab

The default Viewer ("OpenLink Data Explorer (default)") is built into the Browser Extension, and therefore provides the smoothest browsing experience. You can change the RDF Viewer to use any available server which has the right capabilities.

Several known-compatible viewers are offered by the "Viewer" drop down menu as shown below:

OpenLink Data Explorer (default selection)
Zitgist Data Viewer
Marbles
Disco
Tabulator
Custom (URL)

"Custom (URL)" allows for any third party viewer you wish to use. The image below shows a custom URL configuration, which targets the OpenLink AJAX Toolkit-based ODE viewer on the OpenLink-hosted bbc.openlinksw.com server.

The RDF Data Access Tab

The RDF Data Access tab is used for specifying the location of the RDF sponger cartridges to used for sponging the RDF available data from the request URL, and by default uses the Virtuoso sponger cartridges hosted on the OpenLink linkeddata.uriburner.com server or this can be changed to use a Virtuoso instance of ones choice where the require sponger cartridges are loaded, as indicated in the diagram below:

The "RDFizer Service" drop-down menu includes entries for known-supported RDF services that can be used for sponging data:

OpenLink Virtuoso (Sponger) - default sponger method used by the OpenLink Data Explorer
Triplr
Custom (URL)

"Custom (URL)" allows for any third party RDFizer you wish to use, following the form "http://server:port/proxy?url=". The image below shows a custom URL configuration, which targets the Virtuoso Sponger on the OpenLink-hosted bbc.openlinksw.com server.

The "SPARQL Endpoint" drop-down menu gives choice between a Virtuoso endpoint, or a custom URL, as indicated below:

Virtuoso default
Custom (URL)

"Custom (URL)" allows for any third-party SPARQL Endpoint you may wish to use, following the form "http://server:port/sparql?query=". The image below shows a custom URL configuration, which targets the Virtuoso SPARQL Endpoint on the OpenLink-hosted bbc.openlinksw.com server.

Use

The steps to use the OpenLink Data Explorer are simple.

Open any web document.
Send it through to the OpenLink Data Explorer:
- Under the View Menu in Firefox, click "Page Data Sources".
- Right-Click (or Ctrl-Click on Mac) the page or a link, then click "View Data Sources".
An OpenLink Data Explorer interface will load in a new tab and you will be able to seamlessly browse through the Linked Data Web.
View a description of the available Linked data:
- Under the View Menu in Firefox, click "Page Metadata" link.
- Right-Click (or Ctrl-Click on Mac) the page or a link, then click "View Page Metadata".
As shown on the Examples page, a new tab will be opened with a page providing a description of the available Linked data. Alternatively, you can click one of the following bookmarklet links, which you can install in your own browser by dragging the link to your browser's bookmarks toolbar:
- Describe Page (default: XHTML with embedded RDFa)
- Describe Page (RDF) (default format: RDF/XML)
Note that these bookmarklets will load in the same tab, replacing the page being viewed when you click. Also note that these are not limited to use with Firefox; they will work with any HTML Web browser.

The examples page walks through some of the options and functionalities of the OpenLink Data Explorer.

The OpenLink Data Explorer Extension

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