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Database Search Fundamentals: Boolean Operators

Boolean Operators

The 19th century mathematician, George Boole, is credited with formulating the algebraic logic which was foundational in developing modern computing. It is this Boolean Logic which allows you to construct advanced search queries by combining keywords using AND, OR, and NOT to establish relationships between concepts.


Narrows a search by combining keywords to retrieve results which contain both/all concepts.

This is the most restrictive- the more keywords you seek to combine in one search, the fewer results you will get.


Example search:  learning AND memory

Search results = 160,973


Example search:

learning AND memory AND language

Search results = 20,428


Broadens a search by retrieving results which may contain either or both keywords.

This is the most expansive - usually, OR would be used to combine synonyms or closely related concepts.


Example search: learning OR memory

Search results = 4,475,410


Excludes unwanted terms from the search.


This decreases results retrieved by eliminating the keyword after the NOT operator.


Example search:  learning NOT memory

Search results = 3,152,059


Example Search:

memory NOT learning

Search results = 1,164,031