The main trick to searching databases effectively and successfully is to understand how we can connect keywords together when searching databases, whether it is the OSU-OKC Library Catalog, an article database, or search tools such as Google. How you enter your search terms can make all the difference!
For assistance on searching with boolean operators, please call the library, 405-945-3251; email okc.reference@okstate.edu; or stop by the reference desk.
Boolean Logic: A method for combining search terms using operators to limit or expand the numbers of results. Originally developed by the mathematician George Boole in the mid-19th Century.
Boolean Operators: Commands that are used to combine keywords to broaden or narrow the results of a search. Combining terms using operators is sometimes called Boolean searching. Boolean operators are the words AND, OR, NOT, which are used to connect search terms. AND narrows a search by requiring that both terms be present. OR broadens a search by incorporating synonyms or alternate terms. NOT narrows a search by excluding terms. Most databases include other operators, but AND, OR, NOT are the three that will always work.
Venn Diagram: A graphical depiction of Boolean Logic, using intersecting circles to represent search operations.
Nesting: When more than one Boolean operator is used in the same search statement, parenthesis are employed to group concepts together
Boolean operators are words we use to connect search terms in database searches. They originated in a system of logic devised by mathematician George Boole (1815-1864). Boolean logic allows the user to combine words or phrases representing significant concepts in a keyword search of any online database. There are three primary Boolean operators:
AND - The AND operator narrows search results. Each time another concept is added using AND the search becomes more precise.
For Example: If we wanted articles which discuss dogs and cats, we might search our database by entering dogs and cats. The following venn diagram represents how our search is interpreted by the database.
NOTE: In many databases, AND is the implied operator. That is, many databases treat search terms input as dogs cats as dogs AND cats.
OR - The OR operator expands the search by using related terms or synonyms. If your first search results in too few results, can you come up with terms to add in by using OR?
For example: if we wanted articles on dogs or cats, if we were researching housepets, we might enter search words dogs or cats. The following Venn diagram is how the search would be interpreted.
NOT - The NOT operator is used to exclude unwanted records from our results.
For example, if you are researching information on dogs and you notice there are articles in your results which also discuss cats, you might edit your search to dogs not cats (that is, you want every article which discusses dogs, and every time the same article discusses cats, you want to exclude it.) Here is how that search is interpreted.
NESTING OPERATORS
If you are searching several concepts and using Boolean operators you should group concepts together by using parentheses.
For example:
(dogs or canines) not (cats or felines)
(dogs or canines) and (stress or loneliness or anxiety)