Databases

1. Databases

2. 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.

3. 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 can’t really browse a database well. Computers, being inherently unintelligent, don’t always understand what you want.

4. 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.

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

6. Databases • Database Searching—Controlled 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.

8. Databases • Database Searching—Controlled 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. • That’s the point with controlled vocabularies. • These vocabularies are created by people “out there” who then control them.

9. Databases • Database Searching—Controlled 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. • That’s the point with controlled vocabularies. • These vocabularies are created by people “out there” who then control them.

10. Databases • Database Searching—Controlled 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 Today’s World may be labeled with subject heading AGED. • Neither book had any of the actual words of the subject heading in its title.

11. Databases • Database Searching—Controlled 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 somebody’s 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

12. Databases • Database Searching—Controlled 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.

13. Databases • Database Searching—Controlled 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.

14. 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.

15. 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.

16. 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 psychoanalysis—Sigmund Freud. • With the “or” search, one typically gets lots of hits.

17. 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.

18. 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 might=“Mental Health—Religious 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.

19. 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.

20. 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.

21. 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.

22. Databases • Keywords: Boolean Searching • The “Not” Command • Back to looking for cars, the one type of car you’re 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.

23. Databases • Keywords: Boolean Searching • Exceptions • Some databases want you to put your linking words in capital letters—OR 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.”

24. 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.

25. 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.” • “You’re both wrong. Rock is a kind of music.” • Words by themselves don’t really mean anything for certain. They only have a definite meaning when you put them in context.