Boolean Searching is a technique for searching for information in a computer database. It involves combining your search terms (keywords or phrases) using three "operators":
The operator(s) you choose to combine your terms determines how the computer searches its database for those terms and what it presents to you in your results list. It is a very powerful and efficient way of searching. It's a search method that is supported by Encore, the library's research databases and Internet search engines like Google. Once you've mastered the principles of boolean searching you'll be able to use them in a variety of different circumstances.
Combining your search terms with the "and" operator requires the computer to search its database for every record (article, book, etc.) that contains all the words in your search.
For example, let's says we're doing research on the effects of diet on athletes. We might type the following search into the database:
sports and nutrition
The computer will then pull from its database every record that mentions the word sports (left circle in the diagram below) and every record that mentions the word nutrition (right circle).
What it will give us in our results list is every record in which BOTH words appear (i.e. the shaded area in the diagram). If only one word appears in the record, we won't see it.
This is a way of being very specific in your search.
The "or" operator works very differently. It requires the computer to search its database for every record that mentions at least one of your search terms. This is a good way of catching synonyms. Referring back to our example about the dietary needs of athletes, we might want to be sure and catch every mention of both sports and athletics, since they are closely related concepts. So we might search for:
sports or athletics
The computer again goes through its database, pulls out every record that mentions sports and every record that mention athletics.
What it gives us in our results list is everything that it found, every record that mentions either sports or athletics.
This is a way of broadening your searching; retrieving more hits.
The "not" operator isn't used as frequently as the others, but can sometimes be useful. "Not" is a way of stripping out "false hits" (i.e. irrelevant information that nonetheless matches your search terms) because it requires the computer to give us every item that mentions one word but not another. Let's say that we're researching the cowboys who roped steers, herded cattle, and rode off into the Western sunset. But when we search the word "cowboys" we get a lot of information about sports teams in Dallas and Stillwater. So we might do a search like this:
cowboys not football
The computer once again goes through its database and pulls out every record that mentions cowboys and every record that mentions football.
What it gives us, however, are only those records mentioning cowboys in which the word football does NOT appear. If the word football is in the same record as cowboys, we won't see it. So hopefully our hits are more relevant to the kind of cowboy we're researching.
This is a way of being more specific in your search.
So remember how each operator functions . . .
AND/NOT = Narrow a search
OR = Broaden a search