3. Effective Database Searches

Tools to Construct a Search

video View a video demo on these Database Searching Tools (flash file)

AND, OR, NOT (“Boolean Operators”)

After choosing your keywords, you can combine them with AND, OR, or NOT (known in “library-speak” as Boolean operators) to make your search effective. They work as follows:

AND: Narrows your search, because both words must appear in each result item. So, child and asthma requires that both of those words appear, not just one or the other.

OR: Broadens your search, because either of the words is acceptable in the result items. So, baby or infant means that your search will return items containing baby only, and other items containing infant only.

NOT: Eliminates some of your search results, because items containing the word after NOT will be ruled out. So, asthma not pneumonia would return all items that mention asthma, EXCEPT the ones that also mention pneumonia.


Most databases allow you to cut off the end of a word (truncation) with a wildcard character, often an asterisk (*). This allows you to find words with the same root but different endings. Most databases use the asterisk for this purpose, but some use a different symbol. Check the database's Help pages to find out which symbol to use.

Example: child* would get you results that contain any of the words child, children, or childhood.

Watch out for chopping off too much of a word. In a search about automobiles, car* will get you car, cars, and carburetor, but also carries, carnivore, carousel, and a bunch of other words you don't want.

>>Next page: Sample Search

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