Searching a library database is all about combining keywords in a way that the database can understand and that will retrieve the most relevant results. The combination of keywords is called a search statement. Keep in mind that a search statement that is fantastic in one database, may not be useful in another. This is one reason to have a robust list of potential keywords to interchange -- some will work better in one database than another.

Most library databases use the following techniques to combine keywords.

Boolean Operators

Boolean operators (or connectors) are one of the most important ways to combine keywords effectively when searching databases. Boolean operators link search terms together to either narrow or broaden your set of results. The three basic operators are AND, OR, and NOT.

Use AND in a search to:

narrow your results
tell the database that all search terms must be present in the results

Example: "japanese american" AND students AND university will only capture results that mention all of these terms.

Use OR in a search to:

connect two or more similar concepts
broaden your results
tell you the database that any of the search terms can be present in the results

Example: university OR college will capture results that mention either of these terms.

Use NOT in a search to:

exclude words from your search
narrow your search
tell the database to ignore concepts that may be implied by your search terms

Example: students NOT faculty will capture all results that mention students minus any results that mention faculty.

Truncation & Wildcards

Truncation is a technique that broadens searches to include various word endings and spellings. To use truncation in a search, enter the root of a word and put the truncation symbol at the end. The database will return results that include any ending of that root word. For this reason, it is best not to use truncation on keyword that has a very common root that is likely to yield irrelevant variations (e.g. col* for college will also bring up color, collapse, coloratura, etc.).

Wildcards substitute a symbol for one letter or word. This is useful if a word is spelled in different ways, but still has the same meaning.

Example 1: wom!n = woman, women

Example 2: colo?r = color, colour (important when searching sources in British English)

Preferred truncation and wildcard symbols vary by database, but common symbols include *, !, ?, #. For assistance identifying a database's preferred truncation symbol, look for a link to "Help" on the search screen.

Sample Search Statements

Combine keywords with boolean operators and truncation to create search statements to use in a database. If there is only a single search box then use parentheses when using the OR operator. Since some keywords work better than others depending on the database, try a variety of search statements using a range of keywords. Try both complex searches as well as simpler ones. Some possible search statements to try when looking for items on Japanese American college students during World War II:

"japanese american*" and (college or university) and student* and "world war ii"
"national japanese american student relocation council"
(nisei or japanese) and "university of washington"
"world war 1939-1945" and (college* or universit* or "higher education") and "japanese american*"

If using a database with multiple search boxes (look for an advance search option if available and add additional search boxes if needed), omit the AND operator and the parentheses:

sample search. box 1 = "japanese american*" box 2 = college* or universit* box 3 = "world war ii"

Optional Activities:

Watch: Boolean Operators (B.D. Owens Library 3:03 minute)

Content for this page adapted from the UW Libraries Undergraduate Researcher Tutorial.