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Searching Databases

 


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.

Availability of the journals indexed: Databases that contain some full-text articles include General Reference Center and Expanded Academic ASAP. Most citations will lead you to print sources (the journal, magazine or newspaper itself) or microfiche/microfilm formats. If you use a database that indexes materials not held by LLRC, you may need to search the catalogs of nearby libraries to see if you can find the material at one of them. To search a database effectively, you should know how it is organized. 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.