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• Boolean Searching
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Please contact:
James S. Koga
(909) 869-3098
jskoga@csupomona.edu

October 8, 2007

Boolean Searching

Boolean searching is a feature available in most of our databases and in our Library Catalog. The basic boolean operators are OR, AND and NOT. In the venn diagrams below, the shaded part represents the materials that are retrieved.

The OR operator:

When you use "OR" between 2 keywords, you're asking for results that include either of the keywords. This is a good way to increase the number of results and enlarge your search.

Searches for both terms and returns items containing either A or B or both. Examples: sulfur or sulphur global positioning system or gps automobiles or aircraft

See a longer tutorial on boolean searching for the many uses of the "OR" operator.

The AND operator:

When you use "AND" between 2 keywords, you're asking to narrow your search and return only those items with both of the keywords. The more "AND" operators you use, the fewer results will be returned.

Searches for both terms and returns items containing all or terms. Examples: scientists and employment erosion and dunes obesity and children and china

Often, in the sciences, the subject is of the pattern: The effect of A on B.  This translates into the Boolean search A AND B. 

The NOT operator:

When you use the NOT operator, you're asking for results that exclude one of the keywords. This is another way to cut down on the number of results and focus your search. Many databases will not accept a NOT search. Use this operator with caution, as you may inadvertently eliminate useful material

Use NOT to exclude unwanted terms: Examples: Microsoft not Apple aircraft not helicopters java not indonesia

Boolean operators often can be used in combination. Examples:

• (global positioning systems or gps) and automobiles
• scientists and salaries not (education or academia or professors)

Boolean operators are often available on advanced search pages or our databases:

You can sometimes type the boolean operators in the search box (as in "color or colour") or use the pulldowns to change the operators (here set to "and").