Chapter 7 Information from Electronic Fulltext Databases: Special search features

Table of Contents

Electronic databases offer search features that allow you to focus or refine your search.

Computers are literal, as we all know. Let's say you typed Cabrilo (with only one l) instead of Cabrillo in doing a search. The database will (correctly) tell you there is nothing on your topic.

Computers are literal, also, in that they look only for what you tell them to. Let's say you were interested in Latinas. Once you thought about it, you would also be interested in materials that used the word Latina; you'd also be interested in those that used the word Hispanic or Hispanics. Do you type in all 4 words?

Then, there's word order to consider. Let's say you're interested in solar energy as a topic. In searching a database, how could you specify that you wanted to keep the word solar right next to the word energy, and did not want articles with titles like: "Solar Zest and Your Body's Energy Levels?"

Titles often are pretty descriptive of content; if a word is used in an article title, it's likely the article is on that topic. How can you tell a database that you want your word searched in titles only?

Fortunately, electronic databases, as well as the Web search engines covered in the next chapter, offer search features that allow you to focus or refine your search in the ways just indicated.

Since search features vary across databases, the general recommendation is that you look for and read the Help or Tips pages for any database you want to get to know well.

The most common search features are

• Phrase searching
• Field searching
• Use of truncation
• Use of limit commands (e.g., limit by date, language, media types)
• Application of Boolean logic

To do phrase searching, you enclose terms to be searched as a phrase in quotation marks. This holds the search terms together as you have keyed them in. Examples:

• "affirmative action"
• "Martin Luther King"

  If the default setting is already set on exact phrase (or something similar), then the database will search your phrase as you typed it in and you don't have to use the quotation marks (but, usually, you're not penalized for using them).

In field searching, you specify that a keyword or phrase must appear in a specific field in the record. For example, in Google, in the Advanced search mode, you can specify that your keyword or phrase appear in the title of the page, or in the URL of the page.

Truncation is searching using word stems. You enter the first part of a word, then insert a symbol (usually *), and accept any variant spellings. This allows for the retrieval of different word endings (e.g., -ing, -s, -es, -ism, -ist). For example, nurs* as a search term retrieves nurse, nurses, nursing, and also nursery. Terms have to be at least 3 letters long for truncation to work. Although a very handy search technique, not all search engines take truncation -- Google, for example, does not accomodate it.

Limit commands are available in the Advanced modes of the major search engines. You can, for example, search for Web pages first posted, or updated, very recently, from a certain country, in a certain language. This is possible from the Advanced Search screens of Google and AllTheWeb.

Boolean logic is a way of combining terms using AND, OR, NOT, and, sometimes, NEAR. (Who was George Boole?)

Venn diagrams are commonly used to illustrate Boolean search logic. (Who was John Venn?)

Using the AND operator	Using the OR operator
Using the NOT operator	Using the NEAR operator

Who was George Boole? 
George Boole (1815-1864) was an English mathematician.  His An Investigation into the Laws of Thought, on Which are founded the Mathematical Theories of Logic and Probabilities (published in 1854) approached logic in a new way by reducing it to a simple algebra, incorporating logic into mathematics. It began the algebra of logic called Boolean algebra which now finds application in computer construction, switching circuits, and online searching. 

Who was John Venn?
John Venn (1834-1923) was another English mathematician. In the early 1860s, he began to develop Boole's mathematical logic, using what would become known as Venn diagrams to do so. Others had used fairly similar diagrams, but Venn's were considered more descriptive and easier to understand.