Boolean operator searching

The Library offers access to many CD-Rom and remote databases. Each database has unique searching software. One search method common to all of these databases is Boolean operator searching.
The use of Boolean operators lets you refine and customize your search. There are three basic 'Boolean operators'; AND, OR and NOT. These operators are used to combine search terms.
This document will cover the use of the most common operators, AND and OR.

The AND operator

The AND operator is used to retrieve records that are about two concepts. For example; To find records about the Aboriginal art. The search Statement would be:
aboriginal and art
The following Venn diagram illustrates this;

The red area, the intersection of the two circles, indicates those items containing both the search terms.

The AND operator is used to limit the number of records that you retrieve. For example; To find records about the of Australian aboriginal art. The search Statement would be:

Australia and aboriginal and art
The following Venn diagram illustrates this;

The red area, the intersection of the three circles, indicates those items containing all the search terms.

The OR operator

The OR operator is used combine two or more terms that are synonymous. For example; To find records about the beer or ale, the search Statement would be:
beer or ale
The diagram illustrates this;

The red area indicates those items containing either of the search terms. The intersection of the two circles indicates records containing both of the search terms.

OR is used to retrieve more documents.
The OR operator is used to retrieve more documents. For example; To expand the search above to include lager, the search Statement would be:

beer or ale or lager
The following Venn diagram illustrates this search statement;

The red area indicates those items where any one of the terms are present (more than one term may be present).

In Summary.

The AND operator allows you to retrieve articles that are about both of two distinct concepts.
The OR operator, however, is not restrictive at all. It only specifies that you want to retrieve articles that include at least one of your search terms.

Maintained by:
John Banbury,
Network Librarian
Flinders University Library.