Dewey frequently asked questions

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General questions

How do I get updates to the DDC 23 and Abridged 14?

At present, the best sources of updates are WebDewey and Abridged WebDewey, which incorporate all changes to the print editions, plus additional index terms and built numbers, and many other enhancements.

Why issue a new edition of the DDC?

No matter how well designed a classification system is, it must be revised constantly to keep up to date. Changes or relocations that are made represent the consensus of interested professionals. The DDC helps libraries cope with these changes by providing a section in each new edition on important areas of revision. It also lists relocations and reductions and comparative and equivalence tables.

May I use the DDC to organize information on my Web site?

The DDC is owned by OCLC Online Computer Library Center, Incorporated ("OCLC"). We do consider licensing arrangements for the DDC database. To request a licensing proposal, please send an e-mail message to, describing in detail your proposed use of the DDC.

WebDewey general questions

How often is WebDewey updated?

Dewey Services content is updated regularly. WebDewey is the most up to date, authoritative version of DDC 23. Abridged WebDewey is the most up to date, authoritative version of Abridged Edition 14. Details about the most recent enhancements are posted on the Dewey web site. When logged on to WebDewey, click the "Home" link on the footer and click "Updates" on the left navigation bar.

How do I set up the link-to-OPAC feature in WebDewey?

The following interface enhancement is available in both WebDewey and Abridged WebDewey after the November 2011 release:

  • Link to your OPAC - easily send a DDC search from WebDewey (and Abridged WebDewey) to the call number index of your web-based OPAC. For more information about the feature, see the WebDewey/Abridged WebDewey August 2005 Quarterly Update.

What this feature does

Links to your OPAC and sends a DDC number, allowing you to search library catalogs for DDC numbers from within WebDewey (and Abridged WebDewey).

How to set up this feature

While logged on to WebDewey, click the Preferences link to go to the Preferences screen. Note that the Dewey number search for the Library of Congress search is pre-programmed for you.

In the input box, paste or type the URL that's used in your OPAC for a call number search. If you frequently search more than one OPAC, you can store multiple URLs with the OPAC option; the feature routes to the call number index of the OPAC you've selected as your default. Because the URL may be rather long, the text you enter is repeated below the input box so that you can check the accuracy of the URL in its entirety.

Before you save the URL specified in the OPAC URL input box, you can enter a DDC number and test the feature.

Your OPAC must recognize a DDC number within the URL syntax. Example: the OPAC URL for a call number search at Capital University (Columbus, Ohio) is This is the URL you enter if you want the Capital University OPAC to be your default OPAC. To search for the DDC number [DDC#], WebDewey sends:[DDC#]. Your system may require more complex syntax. If you need help with setup, contact your system administrator for the URL, index identifier, and syntax required for call number searches in your OPAC.

Turn off or Adjust Popup Blockers

Software that blocks display of popup advertisements from Web sites can interfere with the link to OPAC feature in Dewey Services. OPAC search results appear in a new browser window, which the popup blocker prevents from opening. For best results, turn off popup blocking software, or if you prefer to keep a popup blocker active, configure the software to allow popup windows from the domain and from the URL used to link to your local library catalog.

Troubleshooting Pointers

Disclaimer: This information is intended to help you implement a link to your OPAC from WebDewey; however, it's not an exhaustive list.

First things first: Those of you with Innovative Interfaces, Inc. OPACs can probably stop reading now; it's likely your URL syntax is simply your library's domain name, and /search/c placed at the end of the URL. (See the Capital University example in the paragraph above, or see the table below.) Now, that was easy, wasn't it?

If the above paragraph didn't help, don't despair.

  1. First, go to your OPAC and do a call number search.
  2. Copy the URL from the result of your search (this URL will be in your browser's address bar). Copy the URL to the input box in the OPAC Options area and look at it carefully--then enter a DDC number (e.g. 641.2) and click Test. (Or see How to set up this feature paragraph above, or the WebDewey/Abridged WebDewey August 2005 Quarterly Update). If your test doesn't work, you'll need to adjust the URL. Below are some pointers on how to adjust the URL.
  3. When you construct the URL that sends a call number search to your OPAC, remember you can:

    1. Rearrange the widgets?Broadly speaking, a widget is the data that occurs between ampersands (or slashes). In many cases, you can rearrange the widget (they're often not order specific) to get the result you want. This means that the ampersand can be moved to another part of the URL without causing the search to fail. This guideline will make more sense as you read on.
    2. Remove the session specific information?Your URL may contain session specific data. You will need to remove this data to prevent a timeout message from your OPAC when you use the link feature in WebDewey. Example: in the following string,


      you'll want to remove the session specific portion of this URL, or: PID=18046&SEQ=20050725145812

      The final correct construction of the URL that sends a Dewey number search to the call number index is,

    3. Move search arguments to the final position in the URL?We mentioned above that your OPAC must recognize a DDC number within the URL syntax, specifically, at the end of the URL. Example: In the following URL,

      the widget &SA=
      SA (refers to search argument) is placed at the end of the URL. If you find a similar syntax in your URL and it's not at the end of the string, move the ampersand and the identifier to the end of the URL, and test it. Now that you know widgets are generally not order specific, you can piece together your URL by placing (if applicable) the ampersand, index identifier, and search argument to the end of the URL. So don't be shy! Move those widgets around! They won't bite!
    4. Try a varying widget identifier?If your URL doesn't work correctly, sometimes it helps to try another variant of that identifier.

      1. Search Argument ( &Search_Arg= vs. &SA=)

        Example: in the following Voyager OPAC URL widget, &Search_Arg= (i.e., Search Argument) is substituted for &SA= (i.e., also Search Argument), but only the second variant works. That is,

        does not work, but
        http ://


The following examples show URLs that work with WebDewey's link to OPAC feature, by OPAC vendor. This list is not exhaustive. If your vendor isn't listed below, it may still work. If your vendor is listed below, but your test doesn't work, it needs adjustment. In this case, talk to your systems administrator.

Vendor/System Template URL Syntax Example that Successfully Sends Call no.

Search from WebDewey to OPAC
COMPanion Corporation/Alexandria







Endeavor Information Systems/Voyager




Ex Libris/ALEPH 500


Innovative Interfaces, Inc./Millennium

WebDewey login

Can I set up an automatic logon?

Yes. If your browser accepts cookies, you can save your authorization and password at the Local Browser Settings option, located at the bottom center of the login screen. This feature lets you login to WebDewey without retyping your authorization and password each time you log on.

WebDewey training

Is there an overview?

Yes, see "WebDewey 2.0: an overview."

Where is the Introduction?

The Introduction is available in the Dewey Services box in the footer of every page of WebDewey.

Where is the Glossary?

The Glossary is available in the Dewey Services box in the footer of every page of WebDewey.

Where are Relocations and Discontinuations?

Relocations and Discontinuations are available in the Dewey Services box in the footer of every page of WebDewey.

Where are main classes and tables?

Both are available via the links in the header and footer of every page of WebDewey.