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Searching in the Databases

This guide provides a brief overview of common search techniques that you can apply to dasebases, catalogs and search engines to retrieve better results.

Using Boolean Operators

What are Boolean operators?

The 3 Basic Boolean operators are AND, OR, and NOT.

Boolean operators are connectors that you can place between your keywords when you perform a search. They connect your search terms together to either narrow or broaden your set of results.

Why use Boolean operators?

Using Boolean operators is the most efficient way to focus your search when a topic contains multiple search terms. Complete sentences are not good searches. When searching a database, Boolean operators make it easier for the database to process the information in the search and give you exactly what you are looking for.

AND

Use AND to

  • narrow your search results
  • tell the database that you want ALL your search terms to appear in the results
  • AND is usually the default operator when you search
  • For example, ocean AND sea:

Boolean expression with AND

OR

Use OR to

  • broaden your search results
  • tell the database that ANY of your search terms can be present in the results
  • connect two or more similar concepts (synonyms)
  • For example, ocean OR sea:

Boolean expression with OR

NOT

Use NOT to

  • limit your search results
  • exclude terms from your search
  • for example, ocean NOT sea:

Boolean expression with NOT

George Boole

The English mathematician George Boole (1815- 1864) was among the founders of modern symbolic logic. His algebra of logic, also called Boolean algebra, is basic to the design of digital computers.