Skip to main content

Boolean, Truncation, and Wildcards: Home

This guide walks you through how to make your search more effective by using boolean operators, truncation and wildcards.

Boolean Operators

Boolean Operators

 

  • Allow a database search to be narrowed, broadened or made more precise.
  • There are three Boolean operators:  AND, OR, and NOT.
  • AND, OR, NOT are inserted between each search term.

 

AND

 

  • Used for narrowing or focusing a search topic. 
  • Specifies that both search terms must be present in the results. 

 

Example: Teenagers AND Violence

 

TEENAGERS Venn diagram for Boolean Operator And - there is a shaded area where the circles overlap representing where results have to contain both search terms Teenagers AND Violence VIOLENCE

 

 

 

 

 

 

OR

 

  • Used for expanding or broadening a search topic
  • Specifies that either search term can be present in the results. 
  • Often used to include synonyms or related terms.


Example: Teenagers OR Juveniles

 

TEENAGERS Venin diagram for Boolean Operator Or - There are two shaded circles representing each search term. OR allows either search term to be included in the results, broadening your search. JUVENILES

 

 

 

 

 

 

NOT

 

  • Used to eliminate false hits, or get rid of that one term that you don't want in your results list. 
  • Specifies that the first term but not the second can be present in the results. 

Example: Teenagers NOT Violence. 

 

TEENAGERS Venn diagram for the Boolean Operator NOT. If each search term is represented by a circle, using NOT excludes results that include the other circle's search term as well as any articles that had both search terms in common. VIOLENCE

 

 

 

 

 

 

Nesting, Truncation and Wildcards

Nesting or Parentheses

 

  • An alternative to a database's Advanced Search
  • Allows you to construct complex searches combining AND, OR, NOT by grouping search terms appropriately

 

Example:

 (Teenagers OR Juveniles) AND Violence

 

 

Truncation

  • Expands the search to locate all words beginning with the same root 
  • Symbol to truncate is usually an asterisk (*)
    • Example: teenwill return teen, teens, teenage, teenager, etc.)
  • Useful to include any variants authors might use to describe their research
  • Not all words can effectively be truncated
    • Example: Trying to truncate woman as wom* will return wombat, womb, as well as woman and women. 

 

Wildcard

 

  • Used in the middle of a word to match usually known variants of a term.
  • A wildcard usually represents a single character
  • Symbol to represent the single character is usually a question mark (?) but this can vary by database. 
    • Example: wom?n will return woman, women, and womyn.

 

Note: The following search tools involve using various symbols.  These symbols change depending on the database's vendor/interface you're dealing with, and the symbols may change over time within one of these vendors/interfaces.  If you have any questions about what symbols are used in a database, check its "Help" section.

 

Do you have any further questions about Boolean Operators and other database tips and tricks?  Chat with a Reference Librarian!