9.4: Using Databases
Boolean Operators
Boolean operators are words that indicate the relationship between search terms. These terms are AND, OR, and NOT. You may have noticed these terms in most databases, often in a drop-down menu next to the search box.
The dropdown in any EBSCO database looks like:
Figure 9.2 Ebsco Database
If you are using a Gale database, the dropdowns will look like this:
Figure 9.3 Gale database
All databases will have Boolean limiters but you may have to look for them.
AND can be used to narrow the number of results. AND forces the database to only retrieve results that list both terms. You can replace cat AND dog with examples that apply to nursing like magnetic resonance imaging AND therapeutics. You will only get results that have both terms in the results.
cat AND dog
Figure 9.4 AND Boolean OperatorOR can be used to broaden the number of results that you retrieve. This is useful for synonyms, or words that mean the same thing. In this example, you could search for cat OR feline. You can also use OR when searching for similar terms. For example, you may need information about household pets, namely dogs or cats. Using OR will retrieve articles that mention either of the terms. A nursing example could be magnetic resonance imaging OR MRI. That way you would get results that had either search term. Databases are very specific and might not recognize that magnetic resonance imaging and MRI are the same thing.
cat OR dog
Figure 9.5 OR Boolean OperatorNOT is used to exclude a term. The order of your terms is important when using NOT. All results that mention the term after NOT will be excluded. NOT should be used sparingly, as it can eliminate relevant results. For example, if I want information about the therapeutic uses of magnets but keep retrieving articles about magnetic resonance imaging. Using NOT eliminates magnetic resonance imaging but I may be missing some information. There may have been articles about the therapeutic use of magnets, that just happen to mention magnetic resonance imaging, but those were excluded. You can see this if you can, mentally, replace cat with magnet and dog with magnetic resonance imaging. For this reason, NOT should be used carefully.
magnet NOT magnetic resonance imaging
cat NOT dog
Figure 9.6 NOT Boolean OperatorFilters/Limiters
Filters, aka limiters, may be used to reduce your search results to a more relevant set. You have probably used filters when shopping online. For example, you would use the “Prime” filter in Amazon to search for Prime-eligible items or maybe you only wanted "4 star ratings" or a specific brand so you would click the box to add those filters to your Amazon search to narrow your results.
To locate limiters, enter your search terms and hit search. On the left side of the screen, scroll down to use the limiters. Common limiters are published dates and subject headings. When you use keywords in a database search, the database looks for all the sources that have your keyword in it. You can use Subject Headings to narrow your search. Subject Headings tell the database that you want only sources that have your subject heading as one of the main topics in the source. Of course, sources often have more than one subject heading and you can use as many subject headings as you like.
Do remember, though, that the point of using limiters is not to narrow your results to just a few articles but to narrow your search to enough relevant articles to support your research assignment.
Figure 9.6 CINAHL Useful Limiters
Two of the most useful limits for health sciences students are the Publication Date and English Language filters. For most assignments, you will need information published in the last 5 years. Filtering for English language will limit your results to those written in English.
Figure 9.6 CINAHL LimitersActivity – Practice a search
Practice a Search
What is a topic in healthcare you would like to know more about? Refer to the previous activity to locate the database CINAHL, and follow these steps to practice a search.
- What keywords should you use? Are there any synonyms you should add?
- Are there any words you can truncate? Where would you truncate?
- Should you try searching a specific field?
- What boolean operators should you use? Remember the OR operator can be used between synonyms, while you may want to use AND to combine different topics.
- What filters should you use? Do you only want recent information? Or only sources written in English?