Boolean Logic consists of three main logical operators or connectors: AND, OR, and NOT
Boolean Operator AND
- Finds sources containing two or more ideas
- The database will only retrieve items containing both words/terms
- AND narrows your search
- You can use AND many times in one search
- Example: books AND censorship
- Example: Jesus AND miracles
Boolean Operator OR
- Use OR when searching for synonyms
- OR tells the database that the words can be used interchangeably, so it will retrieve items containing either word
- Or broadens your search to include synonyms anmd related words or even unrelated words
- You can use OR many times in one search
- Example: books OR films
- Example: Jesus OR Messiah
Boolean Operator NOT
- Use NOT when you wish to exclude records from your search results
- Be careful when using NOT. The term you want may be present in an important way in results that also contain the word you wish to avoid.
- Example: books NOT politics
- Example: trump NOT president [if you are researching the idea of one idea outweighing (or "trumping") another idea, but do not wish to receive results about President Donald Trump]
Combining Operators
- Make complex searches using more than one Boolean operator at a time
- Make complex search terms by putting parentheses around synonyms
- The NOT operator has to go at the end of your search string
- Example: (electronic OR internet OR web) AND (vote OR voting)
- Example: (Jesus OR Messiah OR Christ) AND (miracles OR supernatural OR healing)
