Boolean Searching Via Dialog

 

Boolean Searching: A Definition

 an adaptation of algebraic system to online searching

 principles originated by mathematician George Boole in early 1800s

 primary features:
  1. search language is comprised of

    2. --commands

    --descriptors (subject headings, personal names, etc.)

    --operators

    --proximity connectors

  2. set notation is applied to descriptors

 facilitates more powerful searching (i.e., faster, more accurate) compared with more user friendly techniques

 

Dialog pioneered the application of Boolean principles in automated database searching

 oldest and largest commercial online service

 widely used by businessmen, government personnel, researchers, librarians, etc.

 competitors--e.g., Maxwell, Mead Data, Wilson, Silver Platter--have adopted the Boolean framework with only minor language modifications

 

Basic Commands

b begin (followed by database number) example: b 1

ss select steps (followed by descriptors and/or sets) ss AIDS and treatment

c combine (followed by sets only) c 1 and 4

t type (followed by set #/format #/designated records) t 5/2/all

ds display sets (shows sets with # hits generated so far in db) ds

sf select files (used with Dialindex database groupings) sf papers

save temp (saves searches within db for 1 week) save temp

exs execute (accesses previously saved searches) exs tb007

logoff (enables user to terminate Dialog connection) logoff

 

Descriptors

 can designate any--or all--fields of a record

 fall within 2 types of database vocabularies:
  1. limited

--built around an authority control list of headings

--possible approaches in selecting terms:
    1. thesaurus of descriptors
    2. nesting
    3. truncation
  1. unlimited

--any term can be used with the exception of 8 stop words:

and

or

not

a

an

of

the

or

--there is a better chance of success when using key words such as
    1. personal names
    2. proper nouns

 

Boolean Operators

 and
  1. narrows search
  2. e.g., ss censorship and librar? And high school?

 or
  1. broadens search
  2. e.g., ss car? or automobile?

 not
  1. focuses (selectively narrows) search
  2. e.g., ss soft drinks not diet

 

Proximity Connectors

 designate spatial relationships between words

 major types:

( )

--used in databases with unlimited vocabulary

--indicates that word on right directly follows word on left

--e.g., popular( )music

(_w)

--represents number of words (or less) between left- and right-hand words

--word on left always comes before word on right

--e.g., knights(1w)columbus

(_n)

--represents number of words (or less) between left- and right-hand words

--either word can come first

--e.g., oil(3n)exploration

 

Other useful searching techniques

 Dialindex

 nesting

 truncation

 

Dialindex makes it possible to search 2 or more databases simultaneously

 databases can be designated individually or as part of classed groupings

 3-step process:

b 415

sf papers

ss NAFTA and unemployment

 in order to access contents of records (via type comand) searcher must enter database of choice

 

Nesting is necessary when more than 1 Boolean operator is used in a command string

 designated by parenthesis surrounding "or" and 2 or more descriptors

 ensures that each descriptor with the nest receives the same treatment

 examples:

ss censorship and (classroom or librar?)

ss transportation not (car? or automobile?)

 

Truncation expands the user's chances for obtaining hits

 makes possible all variations of a designated root word

 3 types:
  1. right hand, unlimited

    2. --designated by a question mark following the root word

    --e.g., librar? (accesses library, librarian, librarians, libraries, etc.)

  2. right hand, limited

    3. --designated by a given number of question marks = the same number of letters after root

    --e.g., librar??? ? (accesses librarian, libraries)

  3. internal

--designated by a question mark representing differing letters within a word

--e.g., wom?n (accesses woman, women)

 

Reference tools needed for Dialog searching

 Dialog Complete Database Catalogue

 Dialog Pocket Guide

 Dialog Blue Sheets

 

Sample search sequence

Eric, file 1…

s1 1,218 censorship

s2 5,172 librar?

s3 122,738 high schools

s4 7 censorship and librar? And high schools

Smith, Sam. A Comparison of Librarian and Community Attitudes Regarding Censorship,

Ph.D dissertation, 1991, University of Pittsburgh. 347p

.

You are now ready to access Dialog to practice search techniques: http://www.dialog.com/.