You have already learned that there are various types of information: bibliographic, numeric, textual and graphical. Databases come in a variety of corresponding "flavors" as well: bibliographic, numeric, full-text, and image or graphical databases.
In the past, you may have used printed indexes and card catalogs before to do your research. Nowadays, much information that was once only in paper indexes and catalogs has been converted to an electronic form.
Although we don't always think of print tools like indexes and card catalogs as "databases," they are precisely that because they are organized collections of information.
To be useful, databases have to be structured in some fairly definite ways. Such structure provides organization for massive quantities of data and allows rapid access to specific pieces of information. Databases are made up of units called records.
Each record, in turn, is made up of fields, which are specific categories of data about the item-the title of a book, the author of an article, the publisher (imprint), the publication date.
Familiarity with the structure of records and fields will help you pinpoint specific information quickly when you do database searches.
Your ability to exploit the information within databases hinges on your skill to search these fields.
|Controlled vocabulary||Backhoe Service|
|Title||Digger Dan & Son Inc.|
|Address||402 S. Main|
It's usually easy enough for us to figure out how to search the author or title fields within a database. For example, if we search the author field in Search It for "Twain, Mark", we will retrieve a list of works by that author. Similarly, most people find it intuitive when searching for a particular book to search the title field, or conduct a "title search".
|Controlled vocabulary||Twain, Mark, 1835-1910 -- Manuscripts -- Facsimiles.|
|Title||The Adventures of Tom Sawyer|
|Imprint||Frederick, Md. : University Publications of America. 1982|
There are, of course, other fields within databases you may search. Most commonly, we use databases to search for information on a topic. What is the best way to search databases when you're looking for information on a topic, such as "the elderly and income", for example?
You can search for information on "the elderly and income" in a number of ways within any given database. The best way, usually, to begin your search is by conducting a natural language search (often called a keyword search). In many databases, this is the default search strategy you find when you log into the database. A natural language search does not limit you to searching only one field, but looks in numerous fields to pull together the best information for you.
Have you ever looked up "movies" in the phone book? Chances are you were referred to look under the term "theaters". When you look for information in the phone book, you are forced to use a system of controlled vocabulary. You cannot necessarily find information under terms we might normally use.
|Controlled Vocabulary||Natural Language
(...or terms you're more likely to think of in everyday speech)
|Automobile Repair & Service||Car Repair or Auto Mechanics.....|
|Building Materials||Construction Supplies or Building Supplies...|
These examples convey what controlled vocabulary is all about - a means of controlling or standardizing the many variations in terminology to provide consistency.
1,2,3. no answers
4. title, notes, subjects, other author
Next we will consider the role of controlled vocabulary searching.
We saw in the section above that natural language searches look in several different fields within a database -- perhaps the title field, note field, controlled vocabulary field, and even others. In contrast, when we conduct a controlled vocabulary field, we are searching one narrow, very specific field which contains a very structured language specific to that database. Most often, we find controlled vocabulary terms rather stilted or artificial. For that reason, we often start with natural language searching before moving on to controlled vocabulary searching.
Within a database, controlled vocabulary terms are frequently called subject headings, subject terms, descriptors, or indexing terms. Most often, we find controlled vocabulary terms rather stilted or artificial.
Many databases will provide you a list of controlled vocabulary terms in a thesaurus or index.
Equally important is understanding and using both controlled vocabulary and natural language in database searching. A typical thesaurus for a discipline, such as the Thesaurus of ERIC Descriptors (such thesauri of controlled vocabulary are more often than not available for you to browse in most electronic databases), contains a listing of controlled vocabulary terms. These are standardized terms used to describe the contents of items such as books and journal articles in databases. Controlled vocabulary terms serve to index the contents of books, journal articles and other items in a predictable, standardized way. Controlled vocabulary terms are frequently called subject headings, subject terms, descriptors, or indexing terms.