Search Tips Boolean and Truncation
Boolean Operators, Truncation, and Wild Cards
Believe it or not, computers cannot think. Computers cannot interpret your intent when you type in words. However, a computer will do exactly what you tell it to do when you type in a search. To the computer, your combination of words is nothing more than a collection of characters. It tries to match your exact terms in the exact order you typed them. Most failed searches are the result of poorly constructed search queries.
When you are searching in databases, it is very helpful to use Boolean operators, truncation, and wild cards. These tools will help you to narrow your searches and pull only the information that will be helpful to you.
Boolean operators are words (or, and, not) used to connect search terms to expand (or) or narrow (and, not) a search within a database to locate relevant information. Boolean operators are also called logical operators or connectors.
women OR females
Or retrieves records that contain any of the search terms. It expands the search. Therefore, use "or" in between terms that have the same meaning (synonyms) or equal value to the search.
women AND media
And retrieves records that contain all of the search terms. It narrows or limits the search. Therefore, use "and" in between terms that are required to make the search specific.
image NOT weight
Not eliminates records that contain a search term. It narrows or limits the search. Therefore, use "not" in front of a term to ensure that the search will not include that term. Warning: Some databases use "and not" instead of "not." Check the database help screen.
- Most databases allow for a
symbol to be used at the end of a word to retrieve variant endings of that
word. This is known as truncation. For example,
bank* will retrieve: bank or banks or banking or banker or bankruptcy, etc.
- Be careful using truncation.
Truncating after too few letters will retrieve terms that are not
relevant. For example:
cat* will also retrieve cataclysm, catacomb, catalepsy, catalog, etc.
It's best to use the boolean operator "or" in these instances (cat or cats).
Some databases allow for wild cards to be embedded within a word to replace a single character. For instance, in EBSCO and Infotrac, you can also use the question mark (?) within a word to replace a character. For example:
wom?n will retrieve woman or women
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"Boolean Searching and Truncation." Oviatt Library. California State University Northridge, 09 Oct. 2008. Web. 17 Feb. 2010. <http://library.csun.edu/Research_Assistance/booleansearching.html>.
"Boolean Operators and Truncation Searching." Using and Evaluating Electronic Sources. Minneapolis Community and Technical College, 29 July 2002. Web. 17 Feb. 2010. <http://camellia.shc.edu/literacy/tablesversion/lessons/lesson4/boolean.htm>.