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What are Boolean Operators?

Last Updated: Feb 03, 2017  |  41 Views

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The Boolean operators are three conjunctions (linking words) used by databases to link search terms together: AND, OR, & NOT.

These are the terms you use to combine separate search terms into a search strategy.

Each operator links terms together in a different way to the others, producing markedly different search outcomes.

The chart below indicates how each works:

 Operator   AKA  Principle

 Retrieval    Logic



 Selective  Combiner 

 Only retrieves records in which both  terms are present

 AND =  A+B,    A,B  Small retrieval but highly relevant to topic. 


 Non-selective  Combiner

 Retrieves records wherein both terms  are present, or either term is  present.

 OR =  A+B, A,  B  Large/massive retrieval but high percentage of irrelevant records
 NOT  Excluding  Operator  Only retrieves records wherein excluded term is not present

 NOT =
 A+B, B

 Eliminates every occurence of excluded  term, including records in which desired terms also appear.

For a rough idea of the type of search retrieval each operator garners, take two search terms, combine and search them with each operator in a database and note the size of your search results:

Example: internet, neutrality (database: Academic Search Complete; searched June 21, 2014)

 Search  Strategy

 Result  Tally   Explanation  Retrieval  Logic




     778  Search result is small because only records in which both "Internet" and "Neutrality" are present are retrieved.  AND =  A+B,    A,B




     417,206    Search result is massive because every record in which either term appears (and both together) is being retrieved.   OR =  A+B, A,  B




     410,047    Search result is 7,159 records smaller than the OR search (above) because every occurence of  the term "Neutrality" has been eliminated from search results.  NOT =
 A+B, B






 Searching the term "Neutrality" alone confirms that there are currently 7,159 records in  Academic Search Complete containing this term. Search 3 (above) elminated every record from its search result.

You can use Boolean operators to combine two terms into a simple search, or use several operators and multiple terms to create intricate and powerful search strategies.

If you need assistance building a search strategy using Boolean operators or simply finding the right search terms, please contact the Reference Desk at 903.566.7343 or at

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