Database
Searching
(basic
concepts)
Records
and Fields
Databases are organized
in Records. Each record represents on item - such as a
book or a journal article.
Most databases do
not include the actual text of the item - those that do are called
fulltext databases - most research databases contain bibliographic
citations to articles or other items. Increasingly more
(particularly Web-based) databases are including links to some
fulltext articles.
Within records information
is organized into fields. Each field represents one piece of
information about that item - author, title, abstract, publisher,
subject, text of record, etc.
In most databases
you can specify the field or fields to be searched - field specific
searching. If you do not your search will default to search
all or selected (most used) fields.
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Indexes
and Thesauri
Databases "index"
the words that appear in a database record - this index is often
accessible. Indexers assign descriptive headings using
thesauri (standardized lists of subject terms) to describe the
primary content of an item, for instance Medline uses MeSH headings.
Knowing and using the proper subject terminology will increase
your chances of returning relevant items when searching.
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Boolean
Searching
Boolean searching
is the most powerful concept to understand and master in searching
electronic databases.
All databases have
the capacity to use this tool - most Internet search engines
also can perform searches using boolean operators.
The boolean operators
are: AND OR NOT
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Search
strategy planning
(see
Database Search Worksheet)
Steps in your planning
strategy:
1) Define your question
- your topic should
be fairly specific
- try and formulate
in the form of a question - for example - What herbal remedies
are used for treating flus and colds in children?
2) Analyze your
topic into concepts
- usually two or
three concepts give the best results
3) Choose database(s)
- there may be several
relevant indexes or databases for your topic.
- you may wish to
consult a librarian for suggestions
4) Choose descriptors
or subject terms applicable for each database
- when possible,
use the appropriate thesaurus to find descriptors or subject
terms for the search concepts.
- there may be several
terms defining one concept.
- combine them using
OR.
5) Note that different
databases may have different subject terms for the same concept.
- if no suitable
terms are found in the thesaurus, use your own words to search
the concept as a ëfree textí search in the title,
abstract, etc.
6) Run the search
- specific commands
will vary from one database to another
- refer to documentation
on online help files for specific commands to execute search.
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Boolean
Operators and Parenthesis
Use parenthesis
when constructing multi-layer searches:
- common cold AND
vitamin c OR zinc
In most databases
the above search entered without parenthesis will be interpreted
in the following way:
- (common cold AND
vitamin c) OR zinc
Therefore insert
your own parenthesis to have the search interpreted the way you
intend:
- common cold AND
(vitamin c OR zinc)
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Truncation
Truncation symbols
are used to find words with the same root but variant endings.
Common truncation
symbols are: * ? $
Some database will
automatically treat terms as if truncated without the need to
enter a truncation symbol.
plan* = planning,
planners; planned; plans (also planet so beware).
Truncation symbols
or wildcards can also be used in the middle of the word to look
for variant spellings of a word: analyze or analyze / woman
or women.
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Interpreting
a database record
Often there are
fields displayed which may not be necessary for your purposes. The
info you need to note depends on the type of item. Most commonly,
the important fields to note are:
- Author
- Title
- Journal title or
Source
- Volume, issue,
pages, date
- Descriptors or
Subject Headings
- Abstracts
If the item is a
book or other type of document the publisher name and address
will also be important to note, as well as the date of publication.
Most databases use
abbreviated field labels such as AU, TI etc. Sometimes these
labels are confusing - consult the Help files of the particular
database for assistance in deciphering field labels. You
may need these labels for searching on a specific field.
Note subject headings
or descriptors for items that you particularly like - they may
give you ideas on terms to use when refining your search.
Note that most databases
offer you options for formatting the results of your search -
which fields you want to view, download to a disk and / or print.
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