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Quick explanation of Boolean terms from LMU University library. If the content starts to lose your interest, you can stay for the music.
Sometimes a search can be overly general (results equal too many hits) or overly specific (results equal too few hits). To fine tune your search, you can use AND, OR, and NOT operators to link your search words together. These operators will help you narrow or broaden your search to better express the terms you are looking for and to retrieve the exact information you need quickly.
USING THE "AND" OPERATOR: If you have a search term that is too general, you can add several terms together using "AND". By stringing key terms together, you can further define your search and reduce the number of results. Note: Unless you define a specific search field, the result list will contain references where all your search terms are located in either the citation or full display.
• For example, type eating disorders AND women to find results that refer to both eating disorders and women.
USING THE "OR" OPERATOR: In order to broaden a search, you can link terms together by using the "OR" operator. By using "OR" to link your terms together you can find documents on many topics. Linked by this operator, your words are searched simultaneously and independently of each other.
• As an example, search eating disorders AND women OR self-esteem to find results that reference the terms "eating disorders" and "women", or the term "self-esteem".
USING THE "NOT" OPERATOR: In order to narrow a search, you can link words together by using the "NOT" operator. This operator will help you to filter out specific topics you do not wish included as part of your search.
Type: eating disorders OR women NOT self-esteem to find results that contain the terms "eating disorders" or "women" but not the term "self-esteem".
To further define your results, type: eating disorders AND women AND self-esteem to constrict the search to include all terms linked by the "AND" operator.
In a database, it is helpful to search using keywords. Special connectors between search terms help the database search engine retrieve results relevant to your topic. If you want the search engine to retrieve results based on a phrase rather than individual words, you must add "and" between the terms. The keyword words are AND, OR, and NOT.
Tips
Use AND between different terms
Use OR between terms with similar meaning
The videos provide an introduction to using search terms in a database. Your results will be more accurate using these tools.
Reading about Booleans can sometimes make you feel like your brain is melting. The best approach is to try a variety of search types in Article Quick Search on the UML Library home page and see the difference in results.
Databases are programmed to prioritize Boolean Operators, (AND, OR, NOT and even more complicated ones) This is often called "search precedence" and it influences how your search is performed.
For instance, most databases give AND precedence over OR, meaning terms linked with AND will be searched before those linked with OR, no matter the order they appear in your search.
In any database, using parentheses will override the search precedence.
Examples of Boolean searches using parentheses:
(children OR kids) AND nutrition
Notice that the OR links two synonyms
(elderly OR "older adults") AND (computers OR technology)
You can use two or more sets of parentheses
((teenager OR teen OR adolescent) AND media) NOT television
You can also use parentheses within parentheses.
Notice the effect of the position of the keywords inside parentheses.
