Boolean operators form the basis of database logic. They connect your search words together to either narrow or broaden your set of results. The three basic boolean operators are: AND, OR, and NOT (or the - sign).
Use AND in a search to:
- narrow your results, telling the database that ALL search terms must be present in the resulting records
- example: cloning AND humans AND ethics. In many, but not all, databases, AND is implied.You can search using phrases to make your results more specific. For example: "college students" AND "test anxiety". This way, the phrases show up in the results as you expect them to be.
Use OR in a search to:
- broaden your results, telling the database that ANY of your search terms can be present in the resulting records
- connect two or more similar concepts (synonyms)
- example: cloning OR genetics OR reproduction
Use NOT (or the - sign) in a search to:
- narrow your search, telling the database to ignore concepts that may be implied by your search terms
- exclude words from your search
- example: cloning NOT sheep (or cloning -sheep)