Databases

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Databases
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Databases

• Database Searching
• Definition A database is any organized
  collection of data that can be retrieved using
  organized search procedures.
  
• Phone books are databases of names, addresses and
  phone numbers.
  
• Organized alphabetically and use an organized
  search procedure involving the alphabet to
  retrieve data.
  
• Yellow pages organized by subject, then by
  alphabet.
  

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Databases

• Database Searching
• Computerized databases present new problems
• C. databases are generally much larger than print
  ones.
  
• There are few common conventions for organizing
  and searching, so every new database is a new
  experience.
  
• Unlike a phone book or the old library card
  catalogue, you cant really browse a database
  well. Computers, being inherently unintelligent,
  dont always understand what you want.

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Databases

• Database Searching
• Case Librarian found remnants of a search on a
  computerized periodical index database.
  
• Database had over 1,000,000 journal citations.
• Searcher typed in keyword Johnson, resulting in
  4,386 hits.
  
• What was worse, the searcher had actually started
  pulling each of the 4,386 entries in turn,
  looking for the right one.

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Databases

• Database Searching
• For retrieving information from computer
  databases, there are two basic search tools.
  
• Controlled Vocabularies
• Keywords

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Databases

• Database SearchingControlled Vocabularies
• Most common controlled vocabulary system in North
  America is the Library of Congress Subject
  Headings system, used in most libraries.
  
• How did subject originate? headings
• Library of Congress (LC) predetermined the terms
  by which most things in the world would be called
  and organized these into alphabetical lists.
  
• Some subject headings were easy dogs are Dogs,
  sunflowers are Sunflowers.

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Databases

• Database SearchingControlled Vocabularies
• Some were more difficult.
• What do you call senior citizens? LC chose
  AGED.
  
• TV faith healers are HEALERS IN MASS MEDIA.
• Why? Because LC said so.
• Thats the point with controlled vocabularies.
• These vocabularies are created by people out
  there who then control them.
  

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Databases

• Database SearchingControlled Vocabularies
• Some were more difficult.
• What do you call senior citizens? LC chose
  AGED.
  
• TV faith healers are HEALERS IN MASS MEDIA.
• Why? Because LC said so.
• Thats the point with controlled vocabularies.
• These vocabularies are created by people out
  there who then control them.
  

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Databases

• Database SearchingControlled Vocabularies
• Rule 1 With controlled vocabularies, you have
  to use the subject terms provided by the system.
  No options are allowed.
  
• Book titled Them TV Preachers may have the
  subject heading HEALERS IN MASS MEDIA.
  
• Book called Active Seniors in Todays World may
  be labeled with subject heading AGED.
  
• Neither book had any of the actual words of the
  subject heading in its title.

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Databases

• Database SearchingControlled Vocabularies
• Rule 2 The actual wording of the data record
  (book title or catalogue entry) is not important
  for controlled vocabularies. Subject headings
  are assigned on the basis of somebodys judgment
  as to what the data is about.
• Advantages I have 5 books with following
  titles
  
• Terminal Choices Choosing Life or Death
• Euthanasia The Practice of Death
• The Right to Die

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Databases

• Database SearchingControlled Vocabularies
• All are assigned subject heading EUTHANASIA
• Presented with database to search, main problem
  is retrieval.
  
• Controlled vocabularies the solution.
• Typing word into the computer and getting back a
  book list regardless of the wordings of the
  actual titles.
  
• That is what controlled vocabulary is designed
  for.

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Databases

• Database SearchingControlled Vocabularies
• Rule 3 Use a controlled vocabulary as a search
  tool when you want a collection of data on the
  same subject regardless of what the data actually
  says about itself.
• Most libraries have an edition of the LC subject
  headings in print or a microfiche edition.
  
• Many databases can be searched only by keyword.
• The lack of a controlled vocabulary search option
  can be a disadvantage when all you want is a set
  of data on one subject regardless of what the
  date says about itself.

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Databases

• Keywords
• Rule 1 With keyword searching, what you type is
  what you get. The computer cannot interpret your
  request or give you the next best solution. All
  it can do is identify the words you ask for and
  give you the related data.

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Databases

• Keywords Boolean Searching
• A system to formulate searches where two or more
  terms are used.
  
• The OR Command
• Want all information that has cars in it, but
  know that some people say automobiles.
  
• I tell the computer to look for both words at the
  same time with the OR command.
  
• In a situation in which I am searching for
  synonyms, I use the OR command.

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Databases

• Keywords Boolean Searching
• The OR Command
• Another situation calling for an or search
  might be that in which two concepts are closely
  related, and you might expect data on either of
  them will be useful to you.
• E.g., in search for psychoanalysis, you might
  be well advised to search as well for the father
  of psychoanalysisSigmund Freud.
  
• With the or search, one typically gets lots of
  hits.

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Databases

• Keywords Boolean Searching
• Rule 2 An or search is usually for synonyms
  or for keywords that are already closely related.
  With it, you are trying to anticipate the
  various ways something might be described or
  approached.

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Databases

• Keywords Boolean Searching
• The AND Command
• One of the most profitable uses of keywords is in
  combining topics to narrow down a search.
  
• E.g., a LC subject heading mightMental
  HealthReligious Aspects
  
• What if you wanted to look at information on
  relationship between prayer and mental health?
  
• A subject heading might let you down, but a
  keyword would get you what you want.

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Databases

• Keywords Boolean Searching
• The AND Command
• The formulated keyword search would look like
• prayer and mental
• or
• Prayer and mental and health
• A more complicated formula
• prayer and mental and (health or illness)
• The data will have prayer and mental in it and in
  addition must have either health or illness in
  it.
  

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Databases

• Keywords Boolean Searching
• The AND Command
• Rule 3 A keyword and search is used to
  search for data that relates two topics or
  concepts together. The data found will show the
  effect of the relationship of these topics.

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Databases

• Keywords Boolean Searching
• The AND Command
• Rule 4 And searches will narrow or limit
  your topic. Thus you can expect that you will
  not get as many hits with an and search as
  with an or search.
• Adding more ands simply guarantees fewer hits.
• Outside of or searching, putting more keywords
  on the screen leads to fewer results.

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Databases

• Keywords Boolean Searching
• The Not Command
• Back to looking for cars, the one type of car
  youre not looking for is any car made in
  Europe.
  
• Formula(cars or automobiles) not Europe
• Have added the not and have done a truncation
  on Europe (using an asterisk) so the computer
  could look for Europe and European with a
  single search.

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Databases

• Keywords Boolean Searching
• Exceptions
• Some databases want you to put your linking words
  in capital lettersOR AND NOT
  
• In some databases you can do an and search
  simply by leaving a space between words, but
  other databases will see two words as a phrase
  where the two words have to be found together in
  that order.
• Internet keyword searches often use and
  signs.
  
• In some databases, not has to be expressed as
  and not.

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Databases

• Keywords Boolean Searching
• Exceptions
• Some databases ask you to put quotation marks
  around words that need to appear together.
  
• Complex Keyword Searches
• Some databases allow you to build your own search
  with a grid arrangement that allows you to
  specify what words in what types of combinations
  you want to search.
• Some databases and some search engines are
  playing around with natural language searches
  Boolean searches tend to be more precise.
  

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Information Hierarchies

• If I want to find my way through the information
  fog, I have to learn some theory about the way
  information is structured.
  
• Define ROCK
• A hard object that comes out of the ground.
• No, it is a verb.
• Youre both wrong. Rock is a kind of music.
• Words by themselves dont really mean anything
  for certain. They only have a definite meaning
  when you put them in context.