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Search Strategies: Tips for Working with Databases: Boolean Operators

The following guide is an introduction to creating search terms, and using subject headings, keywords and search syntax.

How to Use AND

Using AND in your search:

  • Narrows, or decreases, the number of results in a search.
  • All terms entered with AND will be present in the resulting records

Here's a visual representation of this example: video games AND violence AND children. The middle triangle, a smaller set of results, will be returned using the search terms with AND.

How to Use OR

Using OR in your search:

  • Broadens, or increases, the number of results in a search.
  • Any term entered with OR will be present in the resulting record.
  • Use OR to group synonyms together

Here's a visual representation of this example: aggression OR bullying OR violence. This expands the results so that all records with any of the search terms is returned.

      

How to Use NOT

Using NOT in your search:

  • Narrows, or decreases, the number of results in a search.
  • Excludes word or phrase following NOT from the result list.

Here's a visual representation of this example: video games NOT Halo. The results list only returns records with video games, but not about the video game Halo.

Boolean Operators Video

Here's a quick video from McMaster University that will explain more about Boolean Operators.

Boolean Modifiers

Now, learn how to format your search for even better results.