What are Boolean Operators? Last Updated: Jun 21, 2018 Views: 65
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
|
Results |
AND |
Selective Combiner |
Only retrieves records in which both terms are present
|
AND = A+B, A,B | Small retrieval but highly relevant to topic. |
OR |
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 = |
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 |
Internet AND Neutrality
|
778 | Search result is small because only records in which both "Internet" and "Neutrality" are present are retrieved. | AND = A+B, A,B |
Internet OR Neutrality
|
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 |
Internet NOT Neutrality
|
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, A+B, B |
Neutrality
|
7,159 |
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 Help Desk at 903.566.7343 or 903.566.7342, by chat, or by email at library@uttyler.edu.
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