3. BOOLEAN SEARCHING
• Also called “Boolean Logic.”
• A type of search syntax or search technique which
helps the user conduct a better, more exact
search.
• It is used when searching using more than one
keyword or phrase.
• When conducting a search, a person uses the
Boolean operators: AND, OR, and NOT.
• These operators are used to link words and phrases
for more precise queries.
4. WHERE DOES BOOLEAN COME FROM?
• Boolean logic takes its name from British
mathematician George Boole (1815-1864), who
wrote about a system of logic designed to produce
better search results by formulating precise queries.
• He called it the "calculus of thought."
• From his writings, we have derived Boolean logic
and its operators: AND, OR, and NOT.
5. HOW BOOLEAN LOGIC WORKS
• It uses the words AND, OR and NOT to search for
items containing both terms, either term, or a term
only if not accompanied by another term.
• All databases and web search engines have help
pages explaining how Boolean logic works in their
specific system.
6. BOOLEAN “AND”
• The Boolean AND actually narrows your search by
retrieving only documents that contain every one of
the keywords you enter. The more terms you
enter, the narrower your search becomes.
EXAMPLE: truth AND justice
EXAMPLE: truth AND justice AND ethics AND
congress
7. BOOLEAN “AND”
A search for „rock
AND roll‟ will locate
all records
containing both the
word “rock” and the
word “roll.” (same as
„all‟)
8. BOOLEAN “OR”
• The Boolean OR expands your search by returning
documents in which either or both keywords
appear. Since the OR operator is usually used for
keywords that are similar or synonymous, the more
keywords you enter, the more documents you will
retrieve.
EXAMPLE: college OR university
EXAMPLE: college OR university OR institution OR
campus
9. BOOLEAN “OR”
• A search for „rock
OR roll‟ will locate
all records
containing either
the word “rock” or
the word “roll” – not
necessaril both.
(same as „any‟)
10. BOOLEAN “NOT” / “AND NOT”
• The Boolean NOT or AND NOT (sometimes typed as
ANDNOT) limits your search by returning only your first
keyword but not the second, even if the first word
appears in that document, too.
EXAMPLE: saturn AND NOT car
EXAMPLE: pepsi AND NOT coke
• Tip: NOT can be dangerous. Let's say you want to search
for items about Mexico, but not New Mexico, so you use
NOT to exclude the word "New" from your retrieved set.
This would prevent you from retrieving an article about
"New regulations in Mexico" because it contained the
word "New," although that wasn't what you intended.
11. BOOLEAN “NOT” / “AND NOT”
• A search for „rock
NOT roll‟ will locate
records containing
the word “rock” but
NOT the word “roll.”
12. BOOLEAN LOGIC
A search for ‘rock AND roll’ will
locate all records containing
both the word "rock" and the
word "roll.” (same as ‘all’)
A search for ‘rock OR roll’
will locate all records
containing either the word
"rock" or the word "roll" --
not necessarily both. (same
as ‘any’)
A search for ‘rock NOT roll’
will locate records
containing the word "rock"
but NOT the word "roll”.
13. NESTING . . . WITH BOOLEAN
OPERATORS
• Nesting, i.e., using parentheses, is an effective way
to combine several search statements into one
search statement. Use parentheses to separate
keywords when you are using more than one
operator and three or more keywords.
EXAMPLE: (hybrid OR electric) AND (Toyota OR
Honda)
• For best results, always enclose OR statements in
parentheses.
14. IMPLIED BOOLEAN OPERATORS
• Implied Boolean operators use the plus (+) and minus (-)
symbols in place of the full Boolean operators, AND and
NOT. Typing a (+) or (-) sign in front of a word will force
the inclusion or exclusion of that word in the search
statement.
EXAMPLE: +dementia -alzheimers
• Similarly, putting double quotation marks (" ") around two
or more words will force them to be searched as a
phrase in that exact order.
EXAMPLE: "green tea”
• In some databases and search engines, you may have to
select “Exact phrase.”
15. THINGS TO CONSIDER WHEN USING
BOOLEAN LOGIC
• Different databases and search engines handle Boolean
operators differently. For example, some accept
NOT, while one accepts ANDNOT as one word, others
AND NOT as two words. Some require the operators to
be typed in capital letters while others do not.
• You may have to indicate if it‟s a Boolean search. This
option would usually be available in the advanced
search option.
• Different databases and search engines may only allow
full Boolean operators in the advanced search
option, while implied Boolean operators may only be
used in the basic search options or vice versa.
16. THINGS TO CONSIDER WHEN USING
BOOLEAN LOGIC
• Some databases and search engines use drop-
down menu options to spell out the Boolean logic in
short phrases.
• For example . . .
• "All of the words" or "Must contain” = AND
• "Any of the words" or "Should contain” = OR
• "Must not contain” = NOT.
17. ACTIVITIES
• Using Google‟s advanced search page, use
different Boolean operators to search for the words
truth and justice.
18. BIBLIOGRAPHY
• Bare Bones Lesson 8: Searching with Boolean logic and
proximity operators. (n.d.). The University of South Carolina
Beaufort. Retrieved February 20, 2013, from
http://www.sc.edu/beaufort/library/pages/bones/lesson8.sht
ml
• Boolean searching: The operators and, and not, or. (1998-
2012). Retrieved February 20, 2013, from
http://www.pandia.com/goalgetter/4.html
• Neyer, L. (2013, February 11). Library database searching.
Library Database Searching. Retrieved February 20, 2013, from
http://www.slideshare.net/lneyer/library-databasesearcing
• Schwartz, K. L. (2009-2012). Skills for online searching. A+
Research & Writing for High School and College Students.
Retrieved February 20, 2013, from
http://www.ipl.org/div/aplus/skills.htm
Notes de l'éditeur
Have any of the students done Boolean Math in math class?
