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What are Boolean Operators?. Mrs. Mersand December 2007. Boolean operators are named after George Boole, an Englishman, who invented them as part of a system of logic in the mid-1800's. The most common Boolean operators are AND, OR, NOT and NEAR, additionally, () can be used - PowerPoint PPT Presentation
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What are Boolean Operators?
Mrs. Mersand
December 2007
Boolean operators are named after George Boole, an Englishman, who invented them as part of a system of logic in the mid-1800's. The most common Boolean
operators are AND, OR, NOT and NEAR, additionally, () can be used
They are used to combine search terms when doing research
In math, they are used to connect logical statements
No…they aren’t leaning
ghosts….
And
Would everybody wearing Jeans, please stand up # _____
Would everybody wearing Sneakers please stand up # _____
Would everybody wearing jeans and sneakers please stand up # _____
Venn Diagram of AND
Jeans Sneakers
AND Explained
Using the operator AND between keywords will limit the results of a search because all the keywords have to be present in order for an item to be retrieved.
OR
Would everybody wearing jeans please stand up #______
Would everybody wearing sneakers please stand up #______
Would everybody wearing jeans OR sneakers please stand up #______
Venn Diagram of OR
Jeans Sneakers
OR Explained
Using the OR operator results in either or both of your search terms appearing in your results.
Using the OR operator will result in a larger number of retrieved items and therefore expands the search.
NOT
The NOT (or AND NOT) operator forbids the word after it from appearing in the items resulting from your search.
Would everybody wearing Jeans but NOT sneakers, please stand up
Venn Diagram for NOT
Jeans Sneakers
NOT Explained
Not helps to limit your search because it takes out a category of undesirable results.
NOT or AND NOT thus narrows or limits a search by excluding the keyword immediately following it.
NEAR
Finds the terms within 10 words of each other
Domestic NEAR Violence would make sure these two words
appeared close enough to each other that they would be referring to domestic violence
( )
Used to group together words or phrases, for example
(domestic NEAR violence) and (police AND trial)
Brings could be used to search for domestic violence that has been interrupted by the police or gone to trial
Order of operators
Just as in math, certain operators are done first. The order for Boolean operators is:( )NEARNOTANDOR
Be sure to use proper search structure
What would the following search bring up?
Dogs AND ((rabies OR rabid) NOT (domestic OR Pet) )
The search will look for the words rabies and rabid Then domestic and pet Then remove all results that contain the words
domestic or pet from the results Then remove anything that does not contain the word
dog from the results
Now lets try some on our own
You should always use more than one search engine when you are doing research
Try thinking out of the box, give Google a break!!
Other options
infomine.ucr.eduwww.lii.orgwww.ipl.orgwww.nettrekker.comwww.altavista.com
www.mama.comwww.dogpile.comwww.yahoo.comwww.surfwax.comwww.ixquick.com