Boolean operators form the basis of mathematical sets and database logic.
Why use Boolean operators?
Truncation
To increase the number of hits retrieved, you might consider using a truncation symbol. Truncation will pick up variations of a word stem. Truncation symbols vary, depending on the database.
e.g., critic* will find critic, critics, criticism, critical, etc.
Wildcard
The wildcard symbol can be used to replace one letter in a word. This will instruct the computer to do a search and match all letters in the word and use any letter to replace the wildcard symbol.
e.g., Wom?n will retrieve records with woman and women.
and did you know that you can use these techniques in the library catalog? search engines?
HENRY example:
(keyword search only) by using biofuel* and energy --- there are 11 titles that contain those keyword
Use AND in a search to:
The purple triangle in the middle of the Venn diagram below represents the result set for this search. It is a small set using AND, the combination of all three search words.
Use OR in a search to:
All three circles represent the result set for this search. It is a big set because any of those words are valid using the OR operator.
Use NOT in a search to:
example: cloning NOT sheep