Boolean Operators

WNCLN Library Catalog FAQ

Keyword Search Tips

Keyword searches look for matches in the author, title, subject headings, and note fields of each catalog record. The most important note field is Contents, which may list individual chapters, essays, short stories, or other parts of a book, anthology or recording. In addition to matching simple phrases, Keyword Search offers powerful tools for refining a search. The table below summarizes these tools.

	Type in Words to search:	EXAMPLES
ADJACENCY (Default)	Multiple words are searched together as one phrase.	`united states supreme court` `body art`
TRUNCATION	Words may be right-hand truncated using an asterisk. Use a single asterisk * to truncate from 0-5 characters. Use a double asterisk ** for open-ended truncation.	`environment* polic` `fyodor dost*`
OPERATORS	Use "and" or "or" to specify multiple words in any field, any order. Use "and not" to exclude words. Parentheses group words together when using Boolean operators.	`north carolina and geography` `(middle age* or medieval) and not middle aged`
FIELDS	Specify fields to search, using field abbreviation. Fields available for this database are a: (author), t: (title), s: (subject), and n: (note.)	`a:twain and t:huck**` `a:united states and (s:disabled or s:handicapped)`
PROXIMITY	Use "near" to specify words within 10 words of each other, in any order. Use "within #" to specify terms which occur within # words of each other in the record.	`appalachian near university` `america within 3 econom*`

Phrase Searching
The library catalog treats adjacent words as a phrase. To perform a Boolean search you must specify the operators. This means that a search for body piercing, will retrieve the phrase body piercing. which will retrieve fewer hits than body and piercing.

How do I use Boolean operators?

The examples on this page illustrate the use of the Boolean operators OR, AND, andAND NOT in Keyword searches. You cannot use Boolean operators in other types of searches.

This section has four parts:

Simple searches with one Boolean operator
Parentheses in searches with more than one Boolean operator
Truncation
Boolean AND NOT

I. Simple searches with one Boolean operator

Imagine that you need to find several books about jazz or blues music for a class assignment. To get an overview of what is available before focusing on some aspect of jazz or blues music, you perform three Keyword searches in the library catalog:

jazz OR blues

broadens

jazz AND blues

AND

narrows

jazz AND NOT blues

AND NOT

excludes

Venn diagrams use circles to visually represent Boolean search results. On this page, each large circle represents a group, or set, of catalog records containing one search term. Each dot represents a single catalog record in our hypothetical search.
Black dots = catalog records that contain the word jazz
White dots = catalog records that contain the word blues
Black/White dots = catalog records that contain bothjazz and blues

Keyword search for: Jazz OR blues

This search locates books that may be about either jazz or blues, or that
compare both forms of music.

		Count the records (dots) retrieved by this search:
		jazz set	21
		blues set	20
		jazz or blues set	32
		Every record in the jazz or blues set contains at least one of the search terms jazz or blues. 9 records that contain both terms appear where the sets overlap.

jazz		blues	These search results demonstrate that you should use OR if you want to retrieve either this term or that term. (Of course, you can OR more than two terms together.) OR always broadens a search.
	<---- jazz or blues ----> (The entire turquoise area)

Keyword search for: jazz AND blues

This search locates books that discuss or compare both jazz and blues.

		Count the records (dots) retrieved by this search:
		jazz set	21
		blues set	20
		jazz and blues set	9
		The result of this search is jazz and blues, the intersection of the jazz set and the blues set. Every record must contain both jazz and blues.

jazz	\|	blues	Use AND when you want to combine search terms. AND always narrows a search.
	jazz and blues (Where the sets overlap)

Keyword search for: jazz AND NOT blues

This search excludes records that contain the term blues.

		Count the records (dots) retrieved by this search:
		jazz set	21
		blues set	20
		jazz and not blues set	12
		The part of the jazz set that does not contain records in the blues set is retrieved as the jazz and not blues set.

jazz	\|	blues	This last search eliminates all records that contain the term blues. If a book compares jazz with blues, you might lose it from your search. Therefore, use AND NOT with restraint and be aware of the consequences.
	jazz AND NOT blues (Turquoise area)

When to use AND NOT and when not to use AND NOT!
AND NOT is appropriate in cases where the same word is used in different contexts. For example, the search vikings and not minnesota would retrieve records about Vikings but not the Minnesota Vikings. If you are doing a history paper about Medieval Viking sagas, this is probably a good thing. If you are writing about pro football, it's not.

II. Using parentheses in searches with more than one Boolean operator

Sometimes a focused search must combine several related words for one idea with another word or words, as in the search: (logging or clearcutting) and rainforests.

In this search, we used Boolean OR to combine the related words: logging OR clearcutting. Then we used Boolean AND to combine these words with rainforests. The parentheses ensure that results are what we expect.

Parentheses indicate relationships between search terms. They force the computer to process your search terms in the order you intend and to combine them in the way you want. Read more about computer search order below.

Computer search order

The library catalog processes your search from left to right, but it processes all the Boolean AND operators BEFORE processing any Boolean OR operators. To change this order, group synonyms (or terms that belong together) with parentheses. Anything enclosed in parentheses is evaluated first. To see how this works, compare the two searches below:

lacrosse or soccer and history Retrieves 50+ items
Combines soccer and history
Retrieves all books about lacrosse
This is not what you wanted!

(lacrosse or soccer) and history Retrieves 25+ items
Combines lacrosse or soccer
"ANDs" those results with history
This is exactly what you wanted!

Of course, you can use more than one OR in a search, as in: (tobacco or smoking) and (cancer or health)

III. Using truncation

If you want to search for part of a word or a whole word that may have several endings, use an asterisk (*) as a "wildcard." It will improve search results and save you time. For example:

To Find: Use:

university or universities universit*

legislate, legislates, legislator, legislators, legislation, or legislating legislat*

IV. Using Boolean AND NOT

How should you use Boolean AND NOT? Very Carefully!

AND NOT eliminates all catalog records that contain the term preceded by AND NOT, but it is a useful tool when a search word has several unrelated meanings. You also can use AND NOT to exclude some commonly discussed aspect of a subject.

For example, if you are doing a term paper on banks or banking in North Carolina, and you keep getting titles about the Outer Banks of North Carolina, you could tighten up your search by using AND NOT:

North Carolina bank* and not outer

If you are researching salamanders but do not want to look at anything about newts, you could do this:

salamanders and not newts

However, you should be aware that any book with chapters about both salamanders and newts will be eliminated from your search results. So, AND NOT is a very risky operator to use in this search!

Using Field Tags

Using field tags in combination with other operators allows you to combine the flexibility of keyword searching with the precision of subject, author or title searching.

For example, using keywords found in subjects will tend to lead you to towards more relevant items while giving you fewer hits to review at the same time!

appalachia* and s:history

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