Boolean is a type of simple programming language that you can use to tell a database what you are searching for more precisely. The three Boolean operators are AND, OR, and NOT.
AND
Use AND in between search terms to tell the database your results must include both terms. This is a way to narrow the results down if you are retrieving too many results that are not relevant. Example: hallucinations AND dementia
OR
Use OR in between search terms to tell the database that your results can include either or both of the search terms. It is effective to use OR for different terms that refer to the same topic, such as teenagers OR teens OR adolescents.
NOT
Use NOT when you want the results to exclude a search term in your results. You can use it to exclude things that are not relevant to your research such as certain populations. Example: hallucinations NOT elderly
Here is a diagram representing Boolean operators:
