Saturday, 13 June 2015

How to structure a Boolean search query

Boolean Searching
  • Objectives:- To learn how to structure a Boolean search query.
  • Method:- You will use Boolean search features at Google.
  • Comments: Boolean operators and brackets can be used to create complex search queries. Not all search engines support full Boolean searching.
A. From the main Google home page : www.google.com

  1. Google does not support full Boolean searching using the AND, OR and NOT operators and brackets.
  2. It does offer the OR operator which can be used with the plus and minus signs.
  3. In the Google search box, enter the following search:
    "meat free" recipes chinese OR indianThe search should retrieve meat free recipes for either Chinese or Indian food.
  4. It is very important that the OR operator is entered in capital letters – otherwise it will be treated as the normal word or which is a stop word and as such will be ignored.
  5. Reference
    The Search Engine Showdown site contains a good overview of how Boolean can be used at Google:
    http://www.searchengineshowdown.com/feat...olean.html

B. Complex Boolean searches cannot be carried out on Google as it does not support the full range of features. AltaVista supports full Boolean.

  1. Go to AltaVista UK at: http://uk.altavista.com/
  2. From the options to the right of the search box select Advanced Search (see Figure 5-1).
     
        On the Advanced Web Search page shown in Figure 5-2, select to Search with… this boolean expression.

   
  1. In the large search box enter the following search : (roman OR greek) AND mythology
  2. The brackets group together certain categories of words and the Boolean operators are used to control how these words are combined.
  3. Press the Find button and review the results.
  4. Note : The Boolean operators are written in capital letters here for clarity – Boolean operators do not have to be written in capitals at AltaVista, but they will only work in the Advanced Search page.
C. The previous search was quite general – just looking for any pages on Roman or Greek mythology. The search can be refined further by using nested brackets. Alter the search to read:
((roman OR greek) AND mythology) AND dictionary
Run the search again. This time you should retrieve sites referring to dictionaries of Greek or Roman mythology.
References

No comments:

Post a Comment