What
is a database?
 A
database is an organized collection of information.
General Reference Center, ERIC, and the LAMP
Online Catalog are examples of databases.
Each
record in a database is composed of the important elements
of information for a particular item. For example,
in the InfoTrac Expanded Academic ASAP database, the
information about a single periodical article is a
record.
Each record
is composed of a set of fields which contain the individual
elements of information. For example, each record in
the CINAHL database includes the fields: title, author,
source, and subject heading.Diagram of the database conceptual
structure:
Types of databases commonly
used in academic research:
1. Bibliographic Database - contains descriptive information (citation
and subject headings) for publications, such as books, periodical articles,
videotapes or government documents.
Index- The LAMP Online Catalog is an example
of an index database.
Example of a record:
Abstracted Index - includes the
citation and a summary of the content of the publication.Example
of a record in ERIC:
2. Full-text Database - contains
the partial or complete text of works, such as
articles, books, poems, and essays. Proquest Newspaper
and Selected GaleNet Resources are databases which
provide full-text articles.
3. Hybrid Database - provides a
combination of different types of records. Expanded
Academic ASAP is an abstracted index that includes
many full-text articles.
List
of LLRC's Electronic Resources
Click on the above link for a list of available Electronic Resources
Selecting a database or index
Selecting the best bibliographic database or print index for your information
need is an important step in any search for information. Each electronic
database and print index is unique in its subject coverage and scope,
although there may be some overlap between them. When choosing a database
or index, it may help to consider the following factors:
The
scope and range: Each database covers specific
subject areas. For print indexes, browse the introductory
material (usually found within the first few pages
or inside the front cover) for information on coverage.
The
types of publications: Some databases and indexes
cover only journal articles, while others may cover
books, government documents, and essays.
The
range of publication dates: Computer indexes will
not usually cover years before the 1970's; some
will only cover a short period of time. Most databases
will give the years they cover on the opening screen.
Place
of publication: Some indexes cover only materials
published in the U.S., while other indexes are
international.
Language
of publication: Materials from non-English speaking
countries are likely to be written in a foreign
language. Most databases identify the language
in which the article is written, and allow for
searches designating specific languages.
Try to answer the following questions
about any electronic database you use:
Does
it allow you to search by subject heading (descriptor)?
Does
it have a thesaurus or subject heading guide? (Some
databases, such as ERIC and CINAHL, have a print
or online thesaurus to help you find the best subject
headings for your topic.)
Can
it search for keywords in specific fields, such as
title or author?
Can
you limit your search by year or language? (The appropriate
commands will vary from database to database.)
Subject
Searching
A subject search involves searching the subject headings of records in
a database. Most databases have subject headings (or descriptors) for
each item that is indexed. These headings are in the subject or descriptor
field. The database producer assigns subject headings to books and articles
from a list of terms used specifically for that database. This list,
called a database thesaurus, ensures that all items about the same topic
have consistent subject headings. Users can then retrieve all the items
on a topic using a single term, even when there may be several good ways
to state a concept. For example, you may want to research the topic death
penalty: Possible ways to state this topic:
Death Penalty
Electrocution
Capital Punishment
Hanging
Cruel and Unusual
Punishment
Death
Row
Lethal
Injection
In the LAMP Online Catalog the subject
heading for death penalty is capital punishment,
but the same term may not be used in all databases.
Here is a Test on SUBJECT HEADINGS
In the following example, which subject heading for heart attacks do
you think would be used in CINAHL, the database used by nurses and
allied health researchers?
Heart Attack
Heart Arrest
Cardiac Arrest
Myocardial Infarction
The thesaurus for the online catalog
is called Library of Congress Subject Headings.
These red books are kept in the Ready Reference
Collection, next to the Reference Desk. If you
are unsure whether a database has a thesaurus,
ask a reference librarian.
Keyword
Searching
A keyword (also called word or free text) search retrieves words or phrases
from several important fields of the records in a database. In most databases
a keyword search finds words in fields that have descriptive content,
such as title, subject/descriptor, and abstract. In some databases, additional
fields may be included in the keyword search. A keyword search usually
retrieves more items than a subject search, but they may not all be relevant.
In a keyword search you can retrieve a number of irrelevant items because
the computer is looking for the exact word you typed, not for the meaning
or context of the word. For example, a search on AIDS will retrieve items
on
aids for the
hearing impaired
school
aids
AIDS (the
disease)
Keyword search is the best method
when
there
is no subject heading for your topic
the
subject heading is too general or too specific
you are
searching for a new trend or concept
the database
does not have subject headings
When searching by keyword, use only
significant words, not common words, such as the,
of, an, and that. Such words may be stop words,
words that occur too frequently to search.
Here is a test on KEYWORDS:
Choose the significant words in the following topic: the effect of advertising
on the body image of women.
What's the Difference?
Subject Searching
Searches subject or descriptor field only
Controlled terminology (from Thesaurus)
High degree of relevancy
Keyword Searching
Searches subject, title, and abstract fields
May search for any significant terms
May retrieve irrelevant items
Identifying
Concepts and Generating Search Terms
The following steps are helpful when preparing for a keyword search:
The following steps are helpful when preparing for a keyword search:
State your topic
as specifically as possible.
Topic: The effect of television viewing on aggressive behavior in children
Identify the main concepts.
1. television viewing
2. aggressive behavior
3. children
Make a list of significant
keywords or phrases for each concept to use as search terms.
A. television viewing
television
television viewing
B. aggressive behavior
aggressive behavior
aggression
fighting
C. children
children
adolescents
Type the keywords, combining
them with Boolean operators (AND, OR, NOT).
Simple
search: television AND aggressive behavior AND
children
Complex
search (using all the keywords): (television viewing
OR television) AND (aggressive behavior OR aggression
OR fighting) AND (children OR adolescents) Instructions
on how to use parentheses for nesting.
AND, OR, and NOT (Boolean
operators)
Using the Boolean operators (AND, OR, NOT), also known as connectors,
to combine keywords in a database search allows you to narrow or expand
your search. To build a complex search using two or more Boolean operators,
you will need to learn the advanced technique of nesting.
Use AND to narrow a search. Both terms must be present in any references
you retrieve
Example: global warming AND forests
Use OR to expand a search. Your search will retrieve records with EITHER
of the terms.
Example: children OR adolescents
OR is most often used to combine synonyms or like terms.
Use NOT to exclude a term. Records with the first term will be retrieved,
but any records with the second term will be eliminated.
Example: special education NOT hyperactivity
Truncation
Truncation allows you to search for a root form of a word and pick up
any ending. Remember that computers find the words exactly as you
type them. Sometimes words have different spellings, or you may need
different forms of the word, such as singular and plural forms and
different suffixes. By truncating a word, you will broaden your search
and ensure that you retrieve all items containing a form of the word
Example: Politic* will
retrieve
politic
politics
political
politically
politician
politicians
Different databases use different
symbols to truncate words. Most use the asterisk
*
Check SEARCH HELP in the database you are using to see what symbol is
used for truncation.
CAUTION! Do not truncate a word too short, or you will retrieve unwanted
matches.
Example:
If you want all forms of the word culture, and you type cul*, you will
retrieve the following that you don't want: cults
cultivate
culinary
culminate
culotte
culprit
The best way to truncate culture
is cultur*.
Phrase
searching (adjacency)
Databases that have adjacency or phrase searching will retrieve two or
more words typed next to each other. Some databases automatically do
adjacent searches. Special commands can be used in other databases to
do adjacent searches. Some databases do not have this capability at all.
Check the database system Help screens for details.
Example: hearing aids.
In a database with adjacency, this search will retrieve materials on
hearing aids, NOT on a Senate hearing concerning AIDS, the disease. In
a database without adjacency, the example above will find both hearing
aids and a Senate hearing on AIDS. Databases that do not have adjacency
usually have an implied AND between two or more words.
Nesting
Nesting involves using parentheses to insure that Boolean operations
are performed in the sequence you intend. This technique allows you
to build a complex search using two or more operators (AND, OR, NOT).
CAUTION! You may not build a good search using more than one Boolean
operator without using nesting.
Example of simple nesting: Find:
smoking AND (adolescents OR teenagers)In this search
the OR operation is nested and will be performed
first. Then the AND operation will be performed.
This search will retrieve items on smoking and
adolescents as well as items on smoking and teenagers.
Example of more complex nesting:
Find: (smoking OR tobacco OR nicotine) AND (adolescents
OR teenagers)The OR operations inside both sets
of parentheses will be performed first, and then
the resulting sets will be combined using the AND
operator. Nesting synonyms in this way can broaden
your search.
BAD Example: Find: smoking OR tobacco
AND adolescents OR teenagers This search will perform
the OR and AND operations in the sequence that
they are typed. This will retrieve items that are
irrelevant! You will retrieve all items about teenagers,
not just those relating to smoking.
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