Boolean Logic
• Think of Boolean Logic as a method to
combine separate topics
• This combination can be shown graphically
with circles representing information topics
• Can help you to narrow a topic
• Can help you to expand a topic
Boolean Operators
• AND both topics must be present in the
record
– AND narrows search results
• OR either topic is present in the record
– OR expands search results
• NOT used to exclude a topic
– NOT eliminates certain search results
Topic:
Electronic Commerce
Database:
Retrieves 9902 citations
Electronic
Commerce
Topic:
Automobile Industry
Database:
Retrieves 17108 citations
Automobile Industry
AND
Narrows Your Search Results
The intersection contains both Electronic Commerce and
Automobile Industry. The overlap containing both topics is
110 records.
Electronic
Commerce Both
Automobile
Industry
Topics
9902
records
17108
records
110
Records
OR
Expands Your Search Results
Either Topic is retrieved. Or is very useful for synonyms when
you don’t know which one might be used in a database
Electronic
Commerce
9902
records
Internet
Commerce
2500
records
12402
Records in total