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College Writing II

Google Vs. The Library

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Simple Introduction: What are Boolean Operators?

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Sample Search Using Boolean Operators

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Boolean Operators

In a database, it is helpful to search using keywords. Special connectors between search terms help the database search engine retrieve results relevant to your topic. If you want the search engine to retrieve results based on a phrase rather than individual words, you must add "and" between the terms. The keyword words are AND, ORand NOT.


Use AND between different terms
Use OR between terms with similar meaning

The videos provide an introduction to using search terms in a database. Your results will be more accurate using these tools.

Reading about Booleans can sometimes make you feel like your brain is melting. The best approach is to try a variety of search types in Article Quick Search on the UML Library home page and see the difference in results.

Databases are programmed to prioritize Boolean Operators, (AND, OR, NOT and even more complicated ones)  This is often called "search precedence" and it influences how your search is performed. 

For instance, most databases give AND precedence over OR, meaning terms linked with AND will be searched before those linked with OR, no matter the order they appear in your search. 

In any database, using parentheses will override the search precedence.

Examples of Boolean searches using parentheses:

(children OR kids) AND nutrition
Notice that the OR links two synonyms

(elderly OR "older adults") AND (computers OR technology)
You can use two or more sets of parentheses

((teenager OR teen OR adolescent) AND media) NOT television
You can also use parentheses within parentheses. 


Notice the effect of the position of the keywords inside parentheses.

boolean operators with parentheses

boolean operator diagram for OR plus parentheses

boolean operators diagram showing no parentheses