How an online library catalog differs from Google

Online library catalog

OPAC = Online public access catalog

Some librarians love to bash Google, as if it has no redeeming qualities for serious research.

Others (well, probably not many librarians) claim that Google is so far superior to online library catalogs that the only way to save them is to make them as much like Google as possible.

Well, I think Google is great, but it is not a library catalog and cannot find things that an online library catalog can.

Google cannot find anything that is not online, including lots of library materials.

Even Google Books has its problems. I will have something more to say about it in another post, but as I was playing around with it, I entered the title of a book that was sitting on my desk, published only about thirty years ago. Google Books couldn’t find it. Then I looked for my own book, The Trombone: Its History and Music, 1697-1811 (New York: Gordon and Breach, 1988) using my name (with middle initial) as the search term. There it was, about six items down. (My second book doesn’t come out until next year. Where did all that other stuff come from?) There was no link for finding it in a library, although it’s quite all right with me if someone wants to buy it instead.

Occasionally my Google searches have turned up journal articles that I would love to read, but when I click on the link, I find I have to sign in. I can’t read it from Google, but if my library subscribes to a database that links to the full text of that journal, I can read it from the library’s website. That, too, is a subject for another post.

If people want to find books, sound recordings, videos, serials, databases, or anything else that’s likely to be in a library, they have to use the catalog. And searching the catalog is fundamentally different from searching Google.

Google looks for web sites, which are scattered on servers all over the world. Its only resource is the language actually used by the site. The only way to search it us by supplying keywords that Google can use to find matching sites.

The online library catalog is a database of records for each title in the library. It works by means of various separate indexes. Besides a general keyword index, there are separate indexes for authors, titles, subjects, etc. They do not necessarily use the same terms as are used in the book (or whatever). Library catalogs and databases use what is called “controlled vocabulary” to look through the records, which is a very powerful search tool that essentially eliminates synonyms. Each record has a description of a publication, based on exact transcription of the title page or its equivalent and some controlled vocabulary.

Part of the complication is that you can’t guess at what the controlled vocabulary is likely to be, but you will discover it by doing a general keyword search and looking at the records that you find. All of the hot links are the controlled vocabulary.

Controlled vocabulary means that there is one and only one official way of expressing, say, a person’s name, regardless of how many different people may have the same name or regardless of how many ways one person’s name may appear in various places.

Suppose you have found a book you like, Pilgrim Fellowship of Faith, by Joseph Ratzinger, and you want to find if he wrote anything more. In case you have forgotten, he is now Pope Benedict XVI.”Ratzinger” will still appear in the description of the book, but the hot link is now for the Pope’s name.

The name Joseph Ratzinger has been reduced to a cross-reference. Why? So that everything by or about him both before and after he became Pope can be found under the same name, no matter which one is actually used for the various publications.

Title: Pilgrim fellowship of faith : the Church as communion / Joseph Cardinal Ratzinger ; edited by Stephan Otto Horn and Vinzenz Pfnür ; translated by Henry Taylor.
Weg gemeinschaft des glaubens: Kirch als communio. English
Personal Author: Benedict XVI, Pope, 1927 Holdings:

Call Number




BR50 .B4613 2005 c.1


Jackson Library — Stacks — Tower 9


Review: Check OneFile for book reviews Publisher: San Francisco, Calif. : Ignatius Press, c2005. Subject Headings: Christianity.
Description: 381 p. ; 21 cm.


If you look at the part labeled “title,” you will notice Joseph Cardinal Ratzinger after the slash. That is the name that appears on the title page. He wasn’t Pope yet when he wrote the book. That part of the record is transcribed exactly from the book itself.

The neat thing is that you can still find the book using Ratzinger as a search term, either as keyword, which picks up what you can see in the record, or even author, which uses magic running in the background.

The “personal author” is identified as Benedict XVI, (etc.). Notice that the last line of the part labeled “title” is “Weg gemeinschaft des glaubens: Kirch als communio. English.” That’s more controlled vocabulary that keeps the translation together with the original German and any translations into other languages that may exist.

If this book were a part of a series, the catalog, would show both the series title as copied from the book and the title from the controlled vocabulary. There are no illustrations, otherwise it would say so under “description.”

Subject headings present special problems. They can come from different vocabularies. If you want to find out about cancer from a library that uses Sears Subject Headings or Library of Congress Subject Heading, the basic term in “Cancer.” But in Medical Subject Headings, it is “Neoplasms.” Once again, the way to find it is to do a keyword search and examine the hotlinks you find.

Title: Strategies for success [electronic resource] : how to write a grant in cancer CAM.

Call Number




SUDOC HE 20.3152:2004011317

Jackson Library

***U.S. Government Web Site***


INTERNET Link: Available online.
Publisher: [Bethesda, Md.] : National Cancer Institute’s Office of Cancer Complementary and Alternative Medicine, Research Development and Support Office, [2003] Subject Headings: Cancer–Alternative treatment–Research grants–United States.
Proposal writing for grants–United States.


Besides demonstrating subject headings, this screenshot rather neatly proves that the online library catalog can find web sites, too. Google does not have a monopoly! It also illustrates part of the problem I mentioned in an earlier post about the lack of a display standard for library catalogs.

There are two subject headings here. It would be better if each started on a new line. But notice that both subject headings include subheadings, separated by dashes. It should be possible to click on any one segment and find anything to the left of it.

That is, clicking on “United States” in either heading would find anything else with that exact heading. Clicking on “Research grants” in the top heading would broaden the search to find material on research grants for alternative treatment of cancer not limited to the United States. Clicking on “Alternative treatments” would broaden the search still more.

Unfortunately, not every library’s catalog is set up to work that way. Sometimes wherever you click, you will retrieve only records that match the entire string. Oh well, maybe it will at least let you copy and paste whatever you really want into another search. Online library catalogs are not perfect, but library blogs are abuzz with ideas on how to improve them.

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