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Librarian's Ultimate Guide to Search Engines

Published on Friday December 8th , 2006

The Librarians Ultimate Guide to Search Engines

Librarians were the ultimate search guides before search was re-invented with the web. They are trusted, credible sources for historical information, and pioneers and innovators of taxonomy of information. Librarians witness, search for, find, organize and catalog knowledge.Online research and the power of the web, have made accessing information only fingertips away from all of us, but the taxonomies and standards used for search will impact how people learn online and off for years to come. Below are some of the things librarians understand about search - and things that anyone doing online research can benefit from.

Brief Recent History Of Search Engines

Web2.0 Search Engines

Text-Based Search Engines - Overview

Glossary: Search Engine + Related

Refining Search Queries

• library taxonomy is usually the same as +library +taxonomy, which is the same as library AND taxonomy. Both words have to appear in the results, but order and proximity may vary. If you want adjacent words (i.e., that specific string), use double quotes: "library taxonomy". Some engines offer a near operator as well, which controls proximity within a certain number of words, say ten.
• Plural forms are usually automatically offered, as are some verb forms of a root word, unless double quotes are used.
• The OR operator might work on exclusion or it work on supplemental rules. For example, libarary OR taxonomy usually means either/both, but could mean one or the other, only (exclusive or), which would make it the same as the next form.
• library NOT taxonomy means return only those web pages with just the word library, never with taxonomy. This is the same, in most engines, as +library -taxonomy.
• Brackets help arrange processing order in complex queries. For example: (EMF OR "electro magnetic fields") AND health means that the SERPs must have the word health and either of the terms EMF or "electro magnetic fields". You can add a bit more leeway in some engines by using (EMF OR (electro magnetic fields)) AND health. This lets the order and proximity of the words electro magnetic fields be more flexible in the results.

Site Operators
These are powerful operators that most engines have but which are not always well-known. While there is a common set of operators, a few engines have their own variations. Here is an amalgamated list. A few references are included after this section, if you are interested in finding out more. All of them consist of a predefined keyword and a semicolon, ":", character, which are then followed by a word or URL or domain name, etc. There should be no spaces on either side of the semicolon.

allinanchor:, inanchor: - Use allinanchor: to specify one or more words that must all be in anchor text. (See definition of anchor text in Glossary above.) Use inanchor to specify one word in anchor text and one or more words in the rest of the document body.
Example: allinanchor:librarian

allintitle: , intitle: - Use allintitle: to specify one or more words that must all be in the title of a web page. Use intitle: to check for a single word in the title, and one or more words in the document body.
Example: allintitle: librarians

allinurl:, inurl: - Use allinurl: to specify one or more words to be checked in the URL of a web page. Use inurl: to check one word in the URL and one or more words in the document body.
Example:allinurl: librarians

cache: - Varies by engine, but it typically shows the last cached version of a page.
Example:cache:http://lii.org

define: - Returns definitions of a specific word, from various sources.
Example: define:librarian

domain:, site: - Use with a domain name to limit searches to pages on that site.
Example:site:stanford.edu.

filetype: - Use with a media file type (e.g., PDF) to limit SERPs to that type of document.
Example: library filetype:xls

info: - Provides engine-specific info about a particular URL or its parent site.
Example: info:becomealibrarian.org

link:, linkto: - Use this to find websites linking to a specific URL or domain.
E.g.: link:www.librarian.net.

related: - Engines determine topic similarity of web pages on different sites. This operator, when used with an URL, will return pages from other sites that are similar.
Example: related:lii.org

There are actually many more specialized operators, some of which are covered in the references below. They are not absolutely necessary, but are useful for power users.


Miscellaneous Operators
Some engines offer additional operator functionality by allowing you to click on a checkbox. Some such features include domain exclusion, choice of site TLDs, and date published range. In some engines, you can specify year range by using something like 2000..2006.


Additional References
Here are a few links to pages about advanced queries.

• Altavista search syntax.
• Google query operators.
• GoogleGuide.
• Berkeley search tutorial.
• Search Engine Weblog: How search engines find you, Simple math in search engines.
• The Learning Site search tutorial.

Google

Yahoo

MSN

Other Textual Search Engines

Below are some of the other text-based search engines, each of which enjoys a varying degree of mild popularity. Not every engine is included below (alphabetical order), but the following should give you a light overview of your options. Defunct engines are not mentioned, and this list is by no means comprehensive.


AllTheWeb



AllTheWeb is a search engine and information portal. Content is divided into web, news, pictures, video, and audio. For example, a search for "trees" under the video category produces SERPS of only video files that have the text string "trees" in the file name. If you were looking for MP3 files of legendary blues master Robert Johnson, you could use the audio tab to get all 2,666 results. (Is that a joke? Who knows. Johnson was said to have made a deal with devil, to be the best blues guitarist ever, and reputed to have 3 graves.) AllTheWeb has a number of advance operators in their query language. A look under the hood reveals that AllTheWeb is just YahooSearch white-labelled.
**Alltheweb utilizes the Yahoo database


AltaVista



Altavista was one of the early challengers for the search engine throne, appearing probably around 1994-95. They were at one time one of the fastest search engines around, based on pure computing horsepower, and were somewhat popular, briefly, until Google appeared. They appear at present to be a white-labelled YahooSearch, with advanced features that are standard.
**Altavista utilizes the Yahoo database


Ask + Excite



Ask.com is part of a group of engines and "information retrieval products" owned by IAC Search & Media. This group includes excite.com, which was once extremely popular when it debuted around 1995, a few years before Google. Ask.com was once called AskJeeves, and was white-labelled by a number of web portals that regular readers visited daily.

Ask also offers some non-standard search functionality (added courtesy of Gary Price)

1) Definition of non-alphanumeric searches
We have started to slowly offer non-alphanumeric searches

2) Zip Code search
Notice the box to help you select the proper state and to see all the Zips for a
specific city.

3) Blog and feed search
NOTE THE pull down boxes to subscribe to a feed (even using a competitors
reader) or post the item with one click using digg, Reddit, etc.

4) New, event listings.
Part of the new AskCity service.

Blogsearch (Google)



Google Blogsearch works in the same way as regular Google, the results are dedicated to weblog sites only. That does not mean blogs are not included in regular Google, but they don't show as prominently there. This way, if you are specifically looking for topics discussed in blogs only, it's easier to find them since many millions of web pages from regular websites have been pre-filtered.



Hotbot (Lycos)



Lycos has enjoyed some popularity and even a loyal following. You can find a summary of advanced features there.



Indeed



Indeed is a job search engine, in case you are looking for a new job in the Library Sciences field. They also have a version for Canadian jobs.



Information



Information appears to be a specialized engine that has also categorizes content into the groups web search, encyclopedia, blogs, articles, groups.



Librarian's Internet Index



The publicly-funded LII, or Librarian's Internet Index, is more of an information portal than a search engine. Each week, hand-selected websites adhering to some current theme are added to the Index, and their content can be searched in the LII. There's also a free newsletter that you can subscribe to. New entries can be subscribed to via the web feed.


Northern Light



Northern Light focuses on offering searches of a wide variety of business content as well as industry journals.



Technorati



Like Google Blogsearch, Technorati is dedicated to weblogs only. However, it's far more than just a search engine and includes many features specifically of use to bloggers. Technorati, amongst other features, lets you know what is popular in a number of blog categories and content types (text, video), as well as in topics. It's also easy to determine what other weblogs are linked to a specific weblog. Finally, in addition to searching indexed blog posts, you can also search through blog post tags and other blog directories.



Digg
Digg is a new form of search engine based on social community as the driving force for relevance. The technique is fairly new, but seems to be catching on with increasing popularity. Digg is currently the 2nd highest trafficked site in the "tech" category according to several resources.

Other Librarian Search Resources

Additional Librarian search resources added courtesy of Gary Price's insight.

• Intute
  Including the Intutue Virtual Training Suite
• Infomine
• AcademicInfo
• Free public database information available with a library card - similar to this (from the San Francisco Public library)
• Greg Notess guide to web engines
  

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Crossing borders: Ajax on Rails Why Ajax works so well with Ruby

Document options Print this page E-mail this page Rate this page Help us improve this content Level: Intermediate Bruce Tate (bruce.tate@j2life.com), President, RapidRed 05 Dec 2006 The hype for Ajax, a technique for making Web pages more interactive, is in overdrive. The Ruby on Rails framework is also flourishing, partly on the strength of its excellent Ajax integration. Find out what makes Ajax on Rails such a powerful combination. The previous two Crossing borders articles (see Resources) walked you through Streamlined, a Rails add-on that makes effective use of scaffolding to generate simple, Ajax-enabled user interfaces quickly. Unless you've been hiding under a rock, you recognize Ajax as a programming technique that uses XML, JavaScript, and Web standards to create highly interactive Web pages, such as those you'll find at Google Maps and hundreds of other sites. Several readers of the Streamlined articles asked me to describe the way Ajax works on Ruby on Rails. This article walks through a couple of simple Ajax examples and, along the way, shows you what makes the Ruby/Ajax combination so successful. In the next article in this series, I'll dig into JavaScript as a programming language. Ajax defined Ajax stands for Asynchronous JavaScript + XML. Jesse James Garrett, an information architect, came up with the term in 2005 to describe a technique that had seen niche use for nearly a decade (see Resources). Ajax use then exploded, with a simultaneous growth in libraries, popular Web sites, and literature. Ajax redefines the basic browser's usage model, which was to render a page at a time. Ajax lets the browser communicate with the server between page updates. The upside is a richer user experience, at the cost of complexity. Ajax works by sending XML between the client and server using JavaScript client-side libraries. Ajax developers can send asynchronous requests from the client at any time, so user interactions can continue while the server processes the requests. This is the flow of an Ajax request: About this series In the Crossing borders series, author Bruce Tate advances the notion that today's Java programmers are well served by learning other approaches and languages. The programming landscape has changed since Java technology was the obvious best choice for all development projects. Other frameworks are shaping the way Java frameworks are built, and the concepts you learn from other languages can inform your Java programming. The Python (or Ruby, or Smalltalk, or ... fill in the blank) code you write can change the way that you approach Java coding. This series introduces you to programming concepts and techniques that are radically different from, but also directly applicable to, Java development. In some cases, you'll need to integrate the technology to take advantage of it. In others, you'll be able to apply the concepts directly. The individual tool isn't as important as the idea that other languages and frameworks can influence developers, frameworks, and even fundamental approaches in the Java community. An event, such as a user mouse click or a programming timer trigger, initiates a JavaScript function. The JavaScript function creates a request for a partial page rather than a full page. JavaScript then sends that request to the Web server via HTTP. This HTTP request invokes a script on the server, such as a Rails controller method or a Java™ servlet. The server script creates an XML document and returns it to the client. Upon receiving the result, the client asynchronously creates, updates, or deletes part of the Web page, such as a list element, div tag, or image. All Ajax applications use an approach that looks something like this sequence. For example, consider an application that lets you maintain dictionary words with their definitions. Old-style applications would force a new page view for you to edit a definition. Ajax would allow in-place editing, by replacing definition text with an entry field, and then replacing that form with the updated definition. The components of an Ajax solution are: A client-side JavaScript library to manage the asynchronous request. A server-side library for dealing with the incoming request and formulating an XML response. A client-side library to deal with the resulting XML. A library -- called the document object model (DOM) -- allowing updates of the existing Web page. Helper routines to deal with inevitable UI and integration issues. This event/request/response/replace model is the core model for most Ajax applications, but if you're new to Ajax, you'd be surprised at the number of available libraries and the broad differences among them. Many Ajax frameworks dot the industry landscape, with frequent overlap and no sure winners. In the Java marketplace alone, dozens of libraries are in use, including Echo, Dojo, DWR, the Google Web Toolkit (GWT), Java Web Parts, AjaxAnywhere, AjaxTags, Scriptaculous, and Prototype. These frameworks use dramatically different approaches. Some, such as GWT, seek to hide any JavaScript by providing Java libraries that generate JavaScript code. Others aim to make JavaScript easier to use. Some are wildly comprehensive, such as Dom4J, and others simply strive to solve one small problem well. As with many popular new technologies, this checkerboard landscape of solutions will be difficult to navigate for quite some time, and the debugging tools, UI practices (such as the Back button), and wise development practices will materialize slowly. The strength of Ajax libraries on the Java platform is their diversity. That's also the weakness, because that diversity breeds indecision, integration concerns, and complexity. With Ruby on Rails, the experience is dramatically different for two reasons. First, Ruby on Rails has one core Web development platform: Ruby on Rails. Second, most of the Ajax development experience on Rails so far has centered around two core frameworks: Scriptaculous and Prototype (see Resources). The Rails approach, using run-time code generation and custom tags, insulates you from the complexities of JavaScript. It's time to see for yourself. As always, if you want to code along, you need to download Rails, which comes with the necessary Ajax frameworks (see Resources). Crack open your Rails environment, and take a look with me. Back to top A simple Rails application without Ajax To use Rails and Ajax, you'll create an empty project and generate a controller with two methods. One controls a simple page, and another sets up an Ajax response. Type the following commands: rails ajax cd ajax script/generate controller ajax show time The first and second lines generate a Rails project and switch to the new directory. The third generates a controller called ajax and views for two actions: show and time. Listing 1 shows the controller code: Listing 1. A controller with two empty methods class AjaxController < ApplicationController def show end def time end end You'll first build two simple views without Ajax and then tie them together with Ajax. Edit the show.rhtml view in app/views/ajax and make it look like Listing 2: Listing 2. A simple view <h1>Ajax show</h1> Click this link to show the current <%= link_to "time", :action => "time" %>. The code in Listings 1 and 2 includes no Ajax support, but I'll dissect it anyway. First, look at the controller in Listing 1. Two empty controller methods process incoming HTTP requests. If you don't explicitly render a view (using a render method), Rails renders the view with the same name as the method. Because the Scriptaculous and Prototype libraries also use HTTP, Rails doesn't need to make any distinction between standard HTTP methods and Ajax methods. Now turn your attention to the view in Listing 2. Most of the code is simple HTML, with the exception of the link_to helper in the second line: <%= link_to "time", :action => "time" %>. As you've seen in previous Crossing borders articles, Ruby replaces the code between <%=h and %> with the value of the expression. In this case, the link-to method is a helper that generates a simple HTML link. You can see the link by executing the code. Start the server by typing script/server and then point your browser to http://localhost:3000/ajax/show. You'll see the view shown in Figure 1: Figure 1. A simple user interface without Ajax In your browser, click the menu options to view the page source (View > Source in Internet Explorer and View > Page Source in Firefox). You'll see the code in Listing 3: Listing 3. The view generated by show.rhtml <h1>Ajax show</h1> Click this link to show the current <a href="/ajax/time">time</a>. Notice the link code in Listing 3. The template shields the Rails user from the tedious and error-prone HTML syntax. (The Ajax code works in the same way: you use helper methods to drop in JavaScript code that manages the remote requests and HTML replacement for you.) If you click the link, you'll see the default view for the time method, but I haven't implemented it yet. To remedy that, replace the time method in app/controllers/ajax_controller.rb with the code in Listing 4. Keeping things simple, I'm rendering the view directly from the controller. Later, I'll clean things up and render a view. Listing 4. Rendering the time def time render_text "The current time is #{Time.now.to_s}" end Now, when you click the link, you get the view in Figure 2: Figure 2. A view with no Ajax You can immediately see a problem with this UI. The two views don't belong on separate pages. The application represents a single concept: click a link to show the time. To update the time repeatedly, you need to click the link and then the Back button each time. You might solve this problem by placing the link and the time on the same page. But if the show page becomes very large or complex, redisplaying the whole page is wasteful and can lead to too much complexity. Back to top Adding Ajax Ajax lets you update just a fragment of your Web page. The Rails libraries do most of the work for you. To add Ajax to this application, you need to do four things: Configure Rails to use JavaScript. Change the time link to submit a JavaScript Ajax request, instead of simply rendering an HTML link. Specify the HTML fragment to be updated. Prepare a place for the updated HTML content. Build a controller method and possibly a view to render the Ajax response. To get started, change the code in app/views/ajax/show.rhtml to look like Listing 5: Listing 5. Changing the show view to use Ajax <%= javascript_include_tag :defaults %> <h1>Ajax show</h1> Click this link to show the current <%= link_to_remote "time", :update => 'time_div', :url => {:action => "time"} %>.<br/> <div id='time_div'> </div> I've made a few changes. First, to handle the configuration, I simply included the requisite JavaScript libraries directly in the view. Usually, I'd have more views, and to avoid repetition I'd include the JavaScript files in a common Rails component, such as a Rails layout. This example has only one view, so I'll keep things simple instead. Second, I changed the link tag to use link_to_remote. You'll see what this link does in a moment. Notice the three parameters: The link text, which is unchanged from the non-Ajax example. An :update parameter. If you've not seen this syntax before, think of :update => 'time_div' as a named parameter, where :update is the name and update_div is the value. This code tells the Prototype library that the results from this link will update the HTML element with the name time_div. :url => {:action => "time"}, which specifies the URL that the link will invoke. :url takes the value of a hash map. In practice, the hash map has only an element for the controller action: :time. In theory, the URL could also include the name of a controller and any optional parameters the controller might need. In Listing 5, you can also see the empty div that Rails will update with the current time. In your browser, load the page http://localhost:3000/ajax/show. Click the link, and you'll see the result in Figure 3: Figure 3. A view with Ajax To get a good feel for what's happening here, view the source for the Web page. Listing 6 shows the code: Listing 6. The results of the show template, enabled for Ajax <script src="/javascripts/prototype.js?1159113688" type="text/javascript"></script> <script src="/javascripts/effects.js?1159113688" type="text/javascript"></script> <script src="/javascripts/dragdrop.js?1159113688" type="text/javascript"></script> <script src="/javascripts/controls.js?1159113688" type="text/javascript"></script> <script src="/javascripts/application.js?1159113688" type="text/javascript"></script> <h1>Ajax show</h1> Click this link to show the current <a href="#" onclick="new Ajax.Updater( 'time_div', '/ajax/time', {asynchronous:true, evalScripts:true}); return false;">time</a>.<br/> <div id='time_div'> </div> Notice the list of JavaScript includes. The Rails helper -- include_javascript_tags :defaults -- built this list for you. Next, instead of an HTML link, you see a JavaScript function call to build a new Ajax.Updater object. The parameter called asynchronous is set to true, as you would expect. Finally, you see no value within the HTML div tags because the initial page had no value there. Back to top Using other Ajax options Ajax can generate powerful behaviors, even some unexpected ones. For example, my users might not notice the updated time link. The link_to_remote option lets you easily apply special effects to the item so the user notices the result. I'll apply some of the effects now. Change the link_to_remote helper in show.rhtml to resemble Listing 7: Listing 7. Adding effects <%= link_to_remote "time", :update => 'time_div', :url => {:action => "time"}, :complete => "new Effect.Highlight('time_div')" %> The best Ajax effects draw temporary attention to your change but don't last forever. Your goal should be to alert users to the change without disrupting their workflow. Techniques like this yellow fading highlight, or content that slides in or fades out, won't be permanently distracting. So far, the link is the only trigger you've seen. Ajax has several others you can use, with some driven by users and others driven by programmatic events, such as a timer. Something like a clock should not necessarily require user intervention. You can update a timer periodically with Ajax with the periodically_call_remote method. Edit the code in show.rhtml to look like Listing 8: Listing 8. Periodically call the remote method <%= javascript_include_tag :defaults %> <h1>Ajax show</h1> <%= periodically_call_remote :update => 'time_div', :url => {:action => "time"}, :frequency => 1.0 %> <div id='time_div'> </div> Figure 4 shows the result: a clock that updates at one-second intervals without requiring user interaction: Figure 4. A clock periodically updated with Ajax Though the code in the Rails view is similar to the version without Ajax, the underlying code is much different: this version uses JavaScript instead of HTML. You can see the code in Listing 9 by viewing the source in your browser: Listing 9. The source for periodically_call_remote <script src="/javascripts/prototype.js?1159113688" type="text/javascript"></script> <script src="/javascripts/effects.js?1159113688" type="text/javascript"></script> <script src="/javascripts/dragdrop.js?1159113688" type="text/javascript"></script> <script src="/javascripts/controls.js?1159113688" type="text/javascript"></script> <script src="/javascripts/application.js?1159113688" type="text/javascript"></script> <h1>Ajax show</h1> <script type="text/javascript"> //<![CDATA[ new PeriodicalExecuter(function() {new Ajax.Updater( 'time_div', '/ajax/time', {asynchronous:true, evalScripts:true})}, 1.0) //]]> </script> <div id='time_div'> </div> Pay close attention to what's happening here. Instead of working with tiny fragments of custom JavaScript, you are effectively working at a higher level of abstraction, and the Ruby on Rails templating system makes the usage model feel quite natural. As I pointed out earlier, I'm rendering text directly from a controller. That simplification makes it easy to get started but won't hold up over time. My views should handle presentation, and my controllers should marshal data between the view and model. This design technique, called model-view-controller (MVC), makes it easier to isolate changes to a view or model. To enable this application for MVC, I can simply let Rails render the default view, and the contents will replace the previous contents of time-div, just as you'd expect. Change the time method in app/controllers/ajax_controller.rb to resemble the code in Listing 10: Listing 10. Refactoring def time @time = Time.now end Change the view in app/views/ajax/time.rhtml to resemble Listing 11: Listing 11. Using a view to render Ajax content <p>The current time is <%=h @time %></p> The controller method sets an instance variable called @time. Because the controller renders nothing explicitly, Rails renders the time.rhtml view. That usage model is exactly the same as rendering a view without Ajax. Once again, you can see that the Rails insulates developers from the differences between applications that use Ajax and those that don't. The usage model is strikingly similar across traditional Web applications and Ajax. More Rails applications take advantage of Ajax because the cost of doing so is so low. Back to top Other uses for Ajax in Rails The Rails Ajax experience is broad and deep -- much deeper than I can cover in a single article or even a series. Rest assured that Rails Ajax support solves some other problems as well. These are some common uses of Ajax in Rails: Submitting remote forms. Ajax forms in Rails work exactly like traditional forms, except you must submit them asynchronously. That means that Forms helper tags in Rails must let you specify a URL to update, and execute visual effects, just as you did with link_to_remote. The Rails submit_to_remote extends a Rails submit helper just as link-to-remote extends the link_to helper. Executing complex scripts. Rails developers often need to execute complex scripts that do more than update a single div and execute effects. Rails provides JavaScript templates for this purpose. With a JavaScript template, you can execute an arbitrary JavaScript script as the result of an Ajax request. Some common uses for these templates, called RJS templates, are updating more than one div, handling form validations, and managing Ajax error scenarios. Completion. You'd often like to offer your users completion, based on items in a database. For example, if the user types Bru, I'd like my application to notice a value of "Bruce Tate" in the database. I can use Ajax to check periodically for changes in a field and send down suggestions for completion as the user types. Dynamically building complex forms. In business, you often need to see part of a completed form before you know which fields a user should complete. For example, a 1040EZ tax form is invalid if a user has certain kinds of income or expenses. With Ajax, you can update the form in progress. Drag and drop. With Rails, you can quickly implement drag-and-drop support with much less effort than most other frameworks require. Back to top Conclusion Ajax is not without its problems. When things go well, the whole experience can be breathtaking. When things break, you may find that debugging takes on a whole new dimension, and debugging techniques and tools still don't match those you'll find in other languages. Ruby on Rails does have one core advantage: simplicity. The Rails wrappers, combined with fantastic community support, make it easy to break into this new world with a very low initial investment. But the Rails support can take you only so far. Two frameworks that do not span the whole Ajax continuum will not satisfy every user. The Java language has many more Ajax frameworks and approaches to choose from. You can find much greater flexibility, and you'll also find a fantastic support base. But flexibility comes at a price. You'll need to pick not only a strong Ajax framework, but also a Web development framework. For example, integrating the JSF framework is a dramatically different experience from integrating Struts. New technologies often call for simplification. Ajax on Rails may be just the ticket for problems that require the sophistication of Ajax in the UI but none of the advanced enterprise-integration features the Java language provides. Next time, I'll take a deeper look into JavaScript. Until then, keep crossing borders. Resources Learn Java To Ruby: Things Every Manager Should Know (Pragmatic Bookshelf, 2006): The author's book about when and where it makes sense to make a switch from Java programming to Ruby on Rails, and how to make it. Beyond Java (O'Reilly, 2005): The author's book about the Java language's rise and plateau and the technologies that could challenge the Java platform in some niches. "Book review: Agile Web Development with Rails" (Darren Torpey, developerWorks, May 2005): Get the scoop on a book that deepens readers' understanding of Rails and the rationale behind agile development approaches. "Ajax: A New Approach to Web Applications" (Jesse James Garrett, Adaptive Path, February 2005): Garrett, who coined the term "Ajax," describes its basic architectural and user experience properties. Scriptaculous and Prototype: The two JavaScript frameworks that power Rails Ajax. Rails Ajax helpers: These helpers shield the Rails developer from the complexities of low-level Ajax programming. Ajax resource center: The developerWorks Ajax portal includes content, blogs, forums and other resources focused on Ajax programming. Ajaxian: This Ajax portal is an excellent discussion of all things related to Ajax. Ajax BluePrints: A discussion of Ajax frameworks and design techniques for the Java programming language. Programming Ruby (Dave Thomas et al., Pragmatic Bookshelf, 2005): A popular book on Ruby programming. The Java technology zone: Hundreds of articles about every aspect of Java programming. Get products and technologies Ruby on Rails: Download the open source Ruby on Rails Web framework. Ruby: Get Ruby from the project Web site. Discuss developerWorks blogs: Get involved in the developerWorks community. About the author Bruce Tate is a father, mountain biker, and kayaker in Austin, Texas. He's the author of three best-selling Java books, including the Jolt winner Better, Faster, Lighter Java. He recently released From Java to Ruby and Rails: Up and Running. He spent 13 years at IBM and later formed the RapidRed consultancy, where he specialized in lightweight development strategies and architectures based on Ruby, and in the Ruby on Rails framework. He is now the CTO of WellGood LLC, a company that is forming a marketplace for nonprofit organizations and charitable giving.

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DOWNLOAD Oracle Database XE Oracle Instant Client Ruby on Rails

TAGS ruby, rubyonrails, All

Ruby on Rails with Oracle FAQs

Exploring Ruby on Rails (RoR)? This FAQ provides basic information about connecting to Oracle, installation, and creating Oracle Database XE + RoR applications.

Published December 2006

Contents

1. WHY RUBY ON RAILS?
2. DEFINITIONS
   • What is Ruby?
   • What is Rails?
   • What is the Model-View-Controller Pattern (MVC)?
   • What is RubyGems?
   • What is OCI8?
3. ORACLE DATABASE CONNECTIONS
   • What do I need to install to run Ruby on Rails using Oracle Database?
   • How can I test OCI8 connectivity?
   • How do I configure an Oracle TNSNAMES.ora entry?
   • What is Oracle Instance Client?
   • What is Oracle Easy Connect Naming?
4. INSTALLATION
   • How do I install Rails and its dependencies?
   • How do I install Rails and its dependencies if a remote installation fails?
   • How do I install Ruby on Rails on the Windows OS?
     1. Install Ruby
     2. Install Oracle Database Connectivity Support
     3. Test the OCI8 connectivity
     4. Install Rails and its dependencies
     5. Verify the Rails Installation
   • How do I install Ruby on Rails on Linux?
     1. Install Ruby
     2. Install Gems
     3. Install OCI8
     4. Install Rails and its dependencies
     5. Verify the Rails installation
   • Errors During Installation
     • How do I handle an error that indicates a RubyGem could not be found?
     • How do I handle an error indicating that a gem could not be found?
     • How do I handle an error that says the service name cannot be resolved?
     • What are some Linux-specific erros that can occur?
5. CREATING AN APPLICATION
   • What are the Database Object Conventions required by Rails when using Oracle?
   • How do I create a basic Rails application?
     1. Configure the Database
     2. Create the Rails application
     3. Configure the application to use the Database
     4. Create the basic Model, Views, and Controller
     5. Test the newly created application

1. WHY RUBY ON RAILS?

Many platforms are available for Web development including Microsoft’s .NET, Java 2 Enterprise Edition, and PHP. Why, then, is there so much interest in a new platform using a relatively unfamiliar language? 

By its design, Ruby on Rails (RoR) lets you develop Web applications very quickly. It does this by adhering to conventions rather than forcing you to make all of your configuration decisions upfront. As a result, RoR lets you develop running applications in a surprisingly short length of time. Once you install Ruby and its various required packages, you can create a minimal Web application by running less than a half-dozen commands and editing one file (database.yml). RoR includes code generators or libraries that address many of the most common Web development tasks. The Ruby language has the object-oriented capabilities of a language like Java, yet you can also use it to create simple scripts. The language’s range of capabilities increases your ability to create applications without having to resort to numerous divergent technologies.

2. DEFINITIONS

What is Ruby?

Ruby is an object-oriented interpreted scripting language created by Yukihiro Matsumoto. Since the mid 1990s, it has grown in popularity in Japan and has gained recent attention as the language behind the Rails framework. You can use the language for a striking variety of functions—from basic scripting to creating Windows applications to developing Web applications. You can start using Rails without extensive knowledge of the language; the Rails framework generates the fundamental classes needed for the Web application and uses reflection to perform object-relational mapping to the database.

What is Rails?

Rails is a Web application and persistence framework created by David Heinemeier Hansson. It includes the infrastructure you need to create database-backed Web applications that use the Model-View-Control (MVC) pattern. Rails has gained attention as a development framework that lets you rapidly create full-featured database-backed Web applications.

What is the Model-View-Controller Pattern (MVC)?

The MVC design pattern is used to separate the following concerns of an application:

This pattern has become popular for Web application development, but it has existed for much longer. Implementations of the pattern have been refined over time and products have been developed to implement it as a framework. You can use Java projects such as Struts and Hibernate to develop applications that leverage the MVC architecture. 

In the Rails framework, ActiveRecord deals with Model concerns. It maps database tables to Ruby objects and provides many other features, including a way to easily access data, represent and traverse relationships between tables, validate data, and get data summaries. It also lets you use straight SQL when desired.

The ActionController coordinates interactions between the View and Model layers (letting users change data through the Web). It routes all requests sent to the Web application, provides a filtering mechanism, Web session access, and other features.

The ActionView deals with what’s actually displayed to the user (generally in the Web browser). Files that contain HTML and Ruby code are appended with an .rhtml extension. Helper classes are also available to provide data formatting.

What is RubyGems?

RubyGems (or simply gems) is the Ruby packaging system used to package Rails components. It provides a standard format for distributing Ruby programs and libraries as well as a tool for managing package installation.

What is OCI8?

The Ruby/Oracle Call Interface (OCI8) is a database driver for Ruby/DBI. RubyDBI provides a database-independent interface for Ruby. You install OCI8 to provide a Ruby interface to the underlying Oracle client software. It’s somewhat analogous to ODBC or JDBC.

3. ORACLE DATABASE CONNECTIONS

What do I need to install to run Ruby on Rails using Oracle Database?

The minimum installation for an RoR Web application that integrates with Oracle Database must include the following:

• Oracle SQL*Plus or Oracle Instant Client software
• Ruby
• Gem
• OCI8
• Rails

The Rails installation includes an application server sufficient for development and small implementations (WEBrick - for WEB server toolkit).

You can use your favorite text editor to edit source code files associated with your Web application.

You’ll need to install either an Oracle Client or Instant Client to work with the OCI8 software. You must configure the TNSNAMES.ora file with the connection information that lets the Oracle client software connect with the database. A great way to get started is to download the free Oracle Database XE, which will install the Oracle client and database.

Strictly speaking, you don’t need SQL*Plus to run Rails applications. There are Rails-based methods (such as migrations) of creating and maintaining database schemas. 

How can I test OCI8 connectivity?

To do a simple test to see if you can query a database that contains the demo (HR) schema, run the following one-liner. The output will be a pipe-delimited file. Make sure the HR schema exists and the account is unlocked and enabled. Substitute the name of your Oracle database (designated below as ORCL) and HR password (indicated as hr_password below) in the following command:

ruby -r oci8 -e "OCI8.new('hr', 'hr_password', 'ORCL').exec('SELECT * FROM jobs
ORDER BY 1') do |r| puts  r.join(' | '); end"

If the connection and query were successful, the output should look something like this:

AC_ACCOUNT | Public Accountant  | 4200 | 9000
AC_MGR | Accounting Manager  | 8200 | 16000
AD_ASST | Administration  Assistant | 3000 | 6000
AD_PRES | President | 20000  | 40000
AD_VP | Administration Vice  President | 15000 | 30000
FI_ACCOUNT | Accountant |  4200 | 9000
FI_MGR | Finance Manager |  8200 | 16000
HR_REP | Human Resources  Representative | 4000 | 9000
IT_PROG | Programmer | 4000  | 10000
MK_MAN | Marketing Manager  | 9000 | 15000
MK_REP | Marketing  Representative | 4000 | 9000
PR_REP | Public Relations  Representative | 4500 | 10500
PU_CLERK | Purchasing Clerk  | 2500 | 5500
PU_MAN | Purchasing Manager  | 8000 | 15000
SA_MAN | Sales Manager |  10000 | 20000
SA_REP | Sales  Representative | 6000 | 12000
SH_CLERK | Shipping Clerk |  2500 | 5500
ST_CLERK | Stock Clerk |  2000 | 5000
ST_MAN | Stock Manager |  5500 | 8500

How do I configure an Oracle TNSNAMES.ora entry?

The TNSNAMES.ora file is a plain-text file used by Oracle to determine the information needed to connect to a database. You’ll typically find it within the Oracle Home /network/admin directory. Every connection includes the server name (or IP address), the port where the Oracle Listener is running, and the name of the database in view.

Here’s an example of a TNS entry that might appear in the file:

ORCL =
  (DESCRIPTION =
    (ADDRESS_LIST =
      (ADDRESS = (PROTOCOL = TCP)(HOST = server.company.com)(PORT = 1521))
    )
    (CONNECT_DATA =
      (SERVICE_NAME = ORCL)
    )
  )

If you’re using Oracle Express Edition, an entry named XE will appear in this file, indicating the database that was created when you installed the software. 

To create a new TNS Entry, you can copy an existing entry and modify the database name, port number, and server name accordingly. Depending on your installation, you might also be able to perform the same task with the Oracle Net Configuration Assistant, which provides a GUI that will edit the file for you.

What is Oracle Instance Client?

Oracle
Instant Client is software that lets you run your applications without installing the standard Oracle client or having an ORACLE_HOME. You can find a description of the software, download the file, and get installation instructions here: http://www.oracle.com/technology/tech/oci/instantclient/index.html

Once you install Oracle Instant Client, you can reference databases using Oracle Easy Connect Naming.

What is Oracle Easy Connect Naming?

If you don’t have a database entry specified in your Oracle TNSNAMES.ora, you can make a connection using easy connect naming.  This lets you connect to an Oracle database using only a TCP/IP connect string made up of a host name, port, and service name. You can run a test of OCI8 using Easy Connect Naming as follows (substituting the appropriate values for your password, server, port, and database):

ruby -r oci8 -e "OCI8.new('hr',  'hr_password', 
'//server.company.com:1521/orcl').exec('SELECT * FROM jobs order  by 1) do |r| 
puts r.join(' | '); end"

4. INSTALLATION

How do I install Rails and its dependencies?

Before you install Rails, you must install Ruby and Gems. 

To install Rails and its dependencies, run the following command:

gem install rails  --include-dependencies

A number of gems are required for Rails to function. These are the versions we used to create the application described in this FAQ:

If you’re behind a firewall or if, for other reasons, you can’t access the remote gems, you can install the software locally.

How do I install Rails and its dependencies if a remote installation fails?

If your machine is located behind a firewall or if, for other reasons, you can’t access the remote gems, download Rails and its dependencies from http://www.rubyforge.org and transfer them to your computer. You can then install each gem locally using a command in the following form:

gem install <gem name up to the dash  preceding the version number>.

For instance:

gem install actionmailer

How do I install Ruby on Rails on the Windows OS?

1. Install Ruby

Installing Ruby on Windows is relatively straightforward: download the appropriate version of Ruby (we used ruby182-15.exe with this article) and double-click the installer. If you’re not sure which components to install, choose Full Install. In any case, you’ll need the RubyGems Package Manager to proceed with the Rails installation.

To make sure that both Ruby and Gems were installed correctly, run gem list --local at the command line to list local gems. The output should looks something like this:

*** LOCAL GEMS ***

fxri (0.3.2)
    Graphical interface to the RI documentation, with search engine.

fxruby (1.2.6)
    FXRuby is the Ruby binding to the FOX GUI toolkit.

sources (0.0.1)
    This package provides download sources for remote gem installation

The installation steps and links to the various resources are listed on the Ruby on Rails Web site (http://www.rubyonrails.org/down).

2. Install Oracle Database Connectivity Support

Download the Ruby interface for Oracle from http://www.rubyforge.org/projects/ruby-oci8. This software provides an interface between Oracle Database 8, Oracle Database 9, or Oracle Database 10 through the standard Oracle Client software or through Instant Client. Make sure you choose the Windows version. Navigate to the directory that contains the Ruby program that you downloaded (ruby-oci8-0[1].1.13-mswin.rb at the time of this writing). Run the following command and choose Yes when prompted:

C:\>ruby ruby-oci8-0[1].1.13-mswin.rb

Copy OCI8.rb to c:/ruby/lib/ruby/site_ruby/1.8/DBD/OCI8
Copy oci8.rb to c:/ruby/lib/ruby/site_ruby/1.8
Copy oci8lib.so to c:/ruby/lib/ruby/site_ruby/1.8/i386-msvcrt
OK?
Enter Yes/No: Yes
Copying OCI8.rb to c:/ruby/lib/ruby/site_ruby/1.8/DBD/OCI8 ... done
Copying oci8.rb to c:/ruby/lib/ruby/site_ruby/1.8 ... done
Copying oci8lib.so to c:/ruby/lib/ruby/site_ruby/1.8/i386-msvcrt ... done
OK

3. Test the OCI8 connectivity

See How can I test OCI8 connectivity?

4. Install Rails and its dependencies

See How do I install Rails and its dependencies?

5. Verify the Rails Installation

Using the following command:

rails -–help

should display a Usage message followed by available options:

Usage: c:/ruby/bin/rails /path/to/your/app [options]
.
.
.

How do I install Ruby on Rails on Linux?

1. Install Ruby

Installing Ruby on Linux requires a few extra steps that may not be familiar to those new to Linux. After downloading the appropriate files, follow the same bas