The key to being a savvy online searcher is to use common search techniques that you can apply to almost any database, including article databases, online catalogs and even commercial search engines.
This is important because searching library databases is a bit different from searching Google.
The techniques described in this section will enable you to quickly retrieve relevant information from the thousands of records in a database.
When you search a database and do not get the results you expect, Ask a Librarian or make a research appointment for advice. Librarians are happy to help you find what you need.
Boolean operators form the basis of mathematical sets and database logic.
- They connect your search words together to either narrow or broaden your set of results.
- The three basic boolean operators are: AND, OR, and NOT.
Why use Boolean operators?
- To focus a search, particularly when your topic contains multiple search terms.
- To connect various pieces of information to find exactly what you're looking for.
- Example:
second creation (title) AND wilmut and campbell (author) AND 2000 (year)
Boolean Operator: Search Order
Databases follow commands you type in and return results based on those commands. Be aware of the logical order in which words are connected when using Boolean operators:
- Databases usually recognize AND as the primary operator, and will connect concepts with AND together first.
- If you use a combination of AND and OR operators in a search, enclose the words to be "ORed" together in parentheses.
Examples:
- ethics AND (cloning OR reproductive techniques)
- (ethic* OR moral*) AND (bioengineering OR cloning)
Use AND in a search to:
- narrow your results
- tell the database that ALL search terms must be present in the resulting records
- example: cloning AND humans AND ethics
The purple triangle in the middle of the Venn diagram below represents the result set for this search. It is a small set using AND, the combination of all three search words.
Be aware: In many, but not all, databases, the AND is implied.
- For example, Google automatically puts an AND in between your search terms.
- Though all your search terms are included in the results, they may not be connected together in the way you want.
- For example, this search: college students test anxiety is translated to: college AND students AND test AND anxiety. The words may appear individually throughout the resulting records.
- You can search using phrases to make your results more specific.
- For example: "college students" AND "test anxiety". This way, the phrases show up in the results as you expect them to be.
Use OR in a search to:
- connect two or more similar concepts (synonyms)
- broaden your results, telling the database that ANY of your search terms can be present in the resulting records
- example: cloning OR genetics OR reproduction
All three circles represent the result set for this search. It is a big set because any of those words are valid using the OR operator.
Use NOT in a search to:
- exclude words from your search
- narrow your search, telling the database to ignore concepts that may be implied by your search terms
- example: cloning NOT sheep
Truncation, also called stemming, is a technique that broadens your search to include various word endings and spellings.
- To use truncation, 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.
- Examples:
child* = child, childs, children, childrens, childhood
genetic* = genetic, genetics, genetically - Truncation symbols may vary by database; common symbols include: *, !, ?, or #
- Root words that have multiple endings. Example: sun = suns, sunshine, sunny, sunlight
- Words that are spelled differently, but mean the same thing. Example: color, colour
- Truncation/wildcard symbols vary by database. Check the help screens to find out which symbols are used.
Wildcards:
Similar to truncation, wildcards substitute a symbol for one letter of a word.
- This is useful if a word is spelled in different ways but still has the same meaning.
- Examples:
wom!n = woman, women
colo?r = color, colour