What are Boolean Operators?

Mrs. Sereno & Mrs. Gadbury 2012

No…they aren’t leaning

ghosts….

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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 additionally, () can be used

In math, they are used to connect logical statements

For accessing information, they are used to combine search terms when doing research

And

Would everybody wearing Jeans, please stand up # _____

Would everybody wearing tennis shoes please stand up # _____

Would everybody wearing jeans AND tennis shoes please stand up # _____

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+

Venn Diagram of AND

War Photography

AND Explained

Using the operator AND between keywords will limitlimit 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 tennis shoes please stand up

#______ Would everybody wearing jeans OR tennis

shoes please stand up #______

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OR

Venn Diagram of OR

War Photography

OR Explained

Using the OR operator results in eithereither or bothboth 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 tennis shoes, please stand up

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Venn Diagram for NOT

Photography War

( )

Used to group together words or phrases, for example

(domestic AND violence) AND (court OR trial)

could be used to search for cases of domestic violence that have been gone to court or trial

Order of operators

Just as in math, certain operators are done first. The order for Boolean operators is:( )NOTANDOR

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 or rabid Then domestic or 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

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Now let’s try one on our own in the WUHS SHARE catalog

I am looking to see if there is any information about ocean mammals in Alaska, like dolphins and porpoises, but I don’t need any more information about whales. What is the best Boolean phrase to build for this search?

(answer on following slide!)

Alaska AND (dolphins or porpoises) NOT whales