Thursday, July 5, 2007

Subject searching in the OPAC

In the library's OPAC (Online Public Access Catalog) there is an option to search for books according to subject. When you do a subject search, the OPAC will find books that have been cataloged with the subject headings that the book happens to be classified under. For example, the book "Data Structures and the Java Collections Framework" has the subject headings "Java (Computer program language)" and "Data Structures (Computer science)."

There are a lot of advantages to searching with subject headings. With subject headings, you can find many similar books even if the authors have used different terminology to describe them. Subject headings are devised in a logical manner, and are arranged according to whether the headings are related terms, narrower in focus or broader in focus, which could help you conduct more precise research. And although keyword searching is very versatile, using a keyword search can yield many irrelevant results if not done carefully. For example, using a keyword such as "Mars" could find books about the planet Mars, the Roman god of the same name, or even a music CD by the rock band called "30 seconds to Mars."

There are advantages to both subject heading and keyword searching. Next week I will discuss keyword searching in more detail.