BWRIT 135: Research Writing (Morse): Boolean Operators
databases don't understand the natural language we speak and need help
understanding what we're looking to find. For this, they require a special set
of conventions, including: Logical or Boolean operators, wildcard and
truncation symbols, and nesting. Databases and internet search engines apply
these rules differently, so check the HELP files in the database you are using
to find out more.
consists of three logical operators (connectors): AND, OR and NOT
Boolean Operator: AND
Finds sources containing two or more ideas
The database will only retrieve items containing both words
AND narrows your search
You can use AND many times in one search
Example: electronic AND voting
Boolean Operator: OR
Use OR when searching for synonyms
OR tells the database that the words can be used interchangeably, so it will retrieve items containing either word
OR broadens your search to include synonyms and related words
You can use OR many times in one search Example: electronic OR internet OR web
Nesting search terms
using: parenthesis ( )
Make a complex search using both AND and OR by placing
parentheses around synonyms so you don't have to repeat searches
Nesting saves you time by allowing you to search
multiple synonyms at once
(electronic OR internet OR web) AND (vote OR voting) - this cuts down on
having to do multiple searches for the combinations of keywords
Use NOT when you wish to exclude records from your search results
Example: pets NOT dogs
Be careful when using NOT! The term you want may be present in an important way in results that also contain the word you wish to avoid
Other Search Tools
The * is a common symbol used to replace any number of letters at the ends of words
Helps find singulars, plurals, and variant endings of words
Check each database's help pages to see which truncation symbol is used in that particular database
Example: vot* finds vote, votes, voter, voting, etc.
Example: communit* finds community, communities
Most databases let you limit search results. Some limits include:
Date of Publication, etc.
Phrases: " "
Enclose phrases in quotation marks when searching the Web or most databases
Phrase searching in individual databases may vary. Check the help pages in each database for additional information.