Boolean Logic for Better Searching

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"Computers are useless. They can only give you answers." --Pablo Picasso

Computerized search mechanisms are based on Boolean logic. When you use the enter code words known as boolean operators you are telling the computer exactly how to perform a search which will be tailored to your specific needs.

The most commonly used code words are: AND, OR, and NOT. The phrase you enter into a search box is called the search string (or syntax)

Here are some diagrams to help explain the effects of these operators.

AND This operator combines the individual words (terms) in order to create a more specific search. It actually NARROWS your search.	Possible search strings (or syntax): cats AND dogs Some search engines use a plus (+) sign instead of the word AND. +Cats +dogs
OR This operator combines possible synonyms of the individual words in order to create a wider search. It actually BROADENS your search.	Possible search strings (or syntax): films OR movies OR motion pictures
NOT  This operator limits (reduces) your search results by excluding specific terms. It actually NARROWS, in a very specific way, your search.	Possible search string (syntax): dolphins NOT football Some search engines use the minus sign (-) instead of the word NOT. +Dolphins -football

Different search engines incorporate Boolean logic in different ways, but they all use it. Some assume AND, some OR. It is important to read the instructions for each search engine before entering your search terms. Info People publishes a nice search engine comparison guide which shows the differences in Boolean syntax used in the different engines: http://infopeople.org/search/chart.html

The use of quotation marks or parenthesis around phrases is a handy device to cause the computer to search for the exact phrase. For instance:

• "American Beauty"
• "computer graphics artist"
• (motion pictures)