Connectors

An effective way to search for information in a database is to combine search terms together.  The concept of Boolean searching is combining two terms together with connectors known as Boolean operators.  The most commonly-used connectors are: AND and OR.  The third connector is NOT, which is used to exclude terms from a search.  

AND narrows a search; you get fewer records, because both concepts must be present in the records found--here the area in color. Use AND to combine different concepts in one search.

OR broadens a search; you get more records because OR includes each of the concepts separately, as well as both concepts when found together. OR is often used to link together related concepts.