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Database Searching

This LibGuide is meant to illustrate database structure and how to search databases according to their design. This LibGuide is meant to be directed toward searching Medical and Life Sciences databases.

Boolean Operators

Boolean operators form the basis of mathematical sets and database logic.

  • They connect your search words together to either narrow or broaden your set of results.
  • The three basic boolean operators are: ANDOR, and NOT.

Why use Boolean operators?

  • To focus a search with AND, particularly when your topic contains multiple search terms.
    • Example: psilocybin AND alcoholism treatment
  • To broaden a search with OR, particularly when you need to add synonyms to a group of search terms.
    • Example: cardiomyopathy OR myocardiopathy OR heart disease
  • To connect various pieces of information to find exactly what you're looking for.
    • Example: second creation (title) AND wilmut and campbell (author) AND 2000 (year)

Search Order

Databases return results based on the commands (searches) you enter. Be aware of the logical order in which words are connected when using Boolean operators: 

  • Databases usually recognize AND as the primary operator, and will connect concepts with AND together first.
  • If you use a combination of AND and OR operators in a search, enclose the words to be OR-ed together in parentheses.