LIS618 lecture 3

1
LIS618 lecture 3

• Thomas Krichel
• 2002-09-23

2
Structure of talk

• The blue sheet
• Working with Dialog
• Nexis.com

3
using dialog

• go to command search
• pass warning screen
• you get to "dialog web command search"
• http//www.dialogweb.com/cgi/logoff?modeguidedur
  l/cgi/dwframe?hrefsearch.html
• searches there do not work well at this level

4
blue sheet

• each database name is linked to a blueish pop-up
  window called the blue sheet for the database
• Contents of bluesheet is covered later
• at this stage we choose a database and hit
  "begin". We see that there is a command selected
  "be numbers" where numbers are the ones for the
  databases selected, separated by comma.

5
database types

• full-text database
• bibliographic databases
• directory databases
• numeric databases
• but they are not classified as such

6
finding a database

• file 411 contains the database of databases
• 'sf category' selects files belonging to a
  category category
• categories are listed at http//library.dialog.com
  /bluesheets
• 'b ref,ref' will select databases

7
closer look at the bluesheet

• file description
• subject coverage (free vocabulary)
• format options, lists all formats
• by number (internal)
• by dialog web format (external, i.e.
  cross-database)
• search options
• basic index, i.e. subject contents
• additional index, i.e. non-subject

8
search options basic index

• select without qualifiers searches in all fields
  in the basic index
• bluesheet lists field indicators available for a
  database
• also note if field is indexed by word or phrase.
  proximity searching only works with word indices.
  when phrases are indexed you don't need proximity
  indicators

9
search in basic index

• basic index is queried through /IN, where IN is a
  field indicator
• Thomas calls this a appending indicator
• several field indicators can be ORed by giving a
  comma separated list, example
• mate/ti,de

10
additional features

• Some databases allow to restrict the search with
  unary expressions
• /ABS require abstract present
• /ENG English language publication
• Some fields are sortable with the sort command,
  i.e. records can be sorted by the values is the
  fields
• Such d are database specific.

11
additional indices

• additional indices lists those terms that can
  lead a query. Often, these are phrase indexed.
• Such fields a queried by prefix INterm where IN
  is the field abbreviator and term is the search
  term
• Thomas calls this a pre-pending indicator

12
the 's' (select) command

• Once issued the "be" command to select a
  database, we issue the "s" command
• "s keywords" where keywords is a Boolean
  expression.
• This will search the selected database in
  full-text view for the Boolean query issued
• probably just searches the main index
• keywords can be added

13
display

• you are allowed to select a format and a number
  of items to be displayed.
• formats vary from database to database, some
  databases can not display certain formats

14
Setting additional terms

• It appear that "drinking and mate" seems a better
  search term
• What other terms to be used?
• matear (suck mate)
• matero (mate sucker)
• cebar (prepare mate)
• cebador (mate preparer)
• prefix queries can be formed by appending a '?'
  to the query term.

15
connectors I

• '(W)' requires terms to appear one after the
  other next to each other e.g. 'yerba(W)mate?'
  matches "yerba mate".
• '(i W)' where i is an integer, means followed by
  at most i words, e.g. 'ceba?(3W)mate?' matches
  "cebar un maravilloso mate" but not "cebador
  guapo mirando un mate"

16
connectors II

• '(N)' requires terms to be next to each other
  e.g. 'yerba(N)mate?' matches "yerba mate" or
  "mate yerba".
• '(i N)' where i is an integer, means proximity by
  at most i words, e.g. 'ceba?(3N)mate?' matches
  "cebar mate" or "matear con la cebadora".
• '(S)' searches for the occurrence of connected
  terms in the same paragraph.

17
connectors III

• (F) words in the same field, no order
• (L) words in the same descriptor field, used to
  link headings and sub-headings. This is a
  hierarchical connector.
• Note connectors are processed left-to-right.
  Use parenthesis whenever in doubt.

18
Boolean operators

• when using Booleans, be aware that "and" has
  higher precedence than "or".
• Thus
• a or b and c
• is not the same as
• (a or b) and c
• but it is
• a or (b and c)

19
executing several searches

• there can be several searches done sequentially,
  and the results sets are saved by the system.
• Each time the system assigns a set number.
• These can be combined in Boolean expressions,
  e.g. 's S1 or S2 and S3'
• Remember that Boolean operations are
  set-theoretic!

20
Reminder fielded searches

• search terms can be limited to fields by
  appending '/field_identifier' to the query term,
  where field_identifier is the identifier of a
  field.
• identifiers of fields are also important in the
  "expand" command

21
common field identifiers

• 'co' company name
• 'de' descriptor
• 'au' author name
• 'df' one-word descriptor
• 'ti' title
• 'cc' classification value
• 'pn' product name
• 'pc' product code
• 'px' company type

22
narrowing by date

• 'PYyyyy', where 'yyyy' is the four digit
  identifier for a year, limits the publication
• 'PDyyyymmdd' where 'yyyy' is the four digit
  identifier for a year, when 'mm' is a two-digit
  identifier

23
expanding queries

• names have to be entered as they appear in the
  database.
• The "expand" command can be used to see varieties
  of spelling of a number.
• It has to be used in conjunction with a field
  identifier, example
• expand aucruz, b?
• to search for misspellings of José Manuel
  Barrueco Cruz

24
expanding queries

• search produces results of the form
• Ref Items Index-term
• Ref is a reference number
• Items is the number of items where the index term
  appears
• Index-term is the index term
• "s Ref" searches for the reference term.

25
DS (display sets)

• This command can be executed any time to review
  the sets that have been formed since the last B
  (begin) command.

the stop words

• an and by for from of the to with

26
add/repeat

• add number, number
• adds databases by files to the last query
• example add 297 to see what the bible says
  about it
• repeat
• repeats previous query with database added

27
the target command

• "target set" where set is a search result fixes
  a subset of the "statistically most relevant
  results"
• new result set is being formed.