Page 129 - DLIS007_LIBRARY AUTOMATION

Library Automation

Notes Most OPACs are Boolean retrieval systems that perform exact matching and require the search
query to be specified as a Boolean expression. Typical search features include the choice of
keyword searching (i.e., searching for individual words in the title and subject fields) or field
searching with automatic truncation (e.g., searching for a whole title or author name), the use of
Boolean operators to combine two or more terms, the use of a truncation symbol, and limiting
a search to specific fields. The onus is on the user to translate the user’s information need into the
subject headings and indexing terms used in the OPAC database and to refine the search based
on the initial search result. Because most OPAC systems now offer Web access, OPAC interfaces
are increasingly Web interfaces in the form of web pages containing HTML forms. Such interfaces
are mainly form-filling interfaces. The user selects the type of search and the fields for searching
either by entering the query in the appropriate input box or by toggling the appropriate checkbox
or radio button. For keyword searching, the search expression can include Boolean operators as
well as indications of which field(s) to search.
OPAC users are heterogeneous, varying widely in background, age, subject interests, and
computer and information literacy. So the OPAC has to be designed to cater to a wide range of
users, ranging from users who have little knowledge of what a catalogue contains and have
little experience with computer terminals to librarians who are experienced in online database
searching and who require the system to have powerful search capabilities.
OPAC is more useful than the traditional card formats because:
(i) The online catalogue does not need to be sorted statically. Here the user can choose the
author, title, keyword, or systematic order dynamically.
(ii) Most online catalogue offer search facility for any word of the title. The goal of the
grammatical word order which is to provide an entry on the word that most users would
look for is reached even better.
(iii) Many online catalogues allow links between several variants of an author’s name. So,
authors can be found both under the original and the standardized name (if entered
properly by the cataloguer).

Online cataloguing has greatly enhanced the usability of catalogues and its origin from the
effort of Machine Readable Cataloguing (MARC) standards in the 1960s. The rules governing
the creation of catalogue MARC records include not only formal cataloguing rules like AACR2
but also the special rules specific to MARC, available from the Library of Congress and also
OCLC.

Example: Online Public Access Catalogue (OPAC) in Erwin Library

You wish to find materials on the topic “evidence-based” using a “word or phrase”
(keyword) search of the OPAC:
1. Access the Erwin Library homepage at http://www.waynecc.edu/library/

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