A keyword search is sometimes called a "Boolean search" and is a commonly used method of searching for specific information in a database. This search technique allows you to retrieve all records from a database containing a particular word or a combination of words. Such a search typically generates many results that may or may not be relevant to the user's query. To obtain more useful results, techniques such as Boolean operators, truncation and nesting can be used.
When performing a keyword search, the words "and," "or" and "not" are known as Boolean operators. Some search engines allow the substitution of symbols such as the plus sign (+) in place of "and" and the minus sign (-) to denote "not."
Using Boolean operators in a search query generates results that are more specific to your needs. For example, the query "milk and cookies and chocolate" will retrieve only documents containing all three words. On the other hand, "milk or chocolate or cookies" will broaden the search, retrieving all documents with one or more of these words. The query "milk and cookies not chocolate" will retrieve all results containing both milk and cookies but documents that contain the word chocolate will be excluded.
Truncation and Nesting
Truncation allows the user to search for all terms with the root word. Different search engines use different symbols for truncation, but the asterisk is quite commonly used after the word to symbolize truncation. For example, 'comp*' will generate results with words like computer, computing, comptroller, compete, competition, competitive and competitor.
Some search engines allow the use of parenthesis to make groups of your search words. This technique is called nesting. For example, "English (British or American)" will generate results with the word "English" and at least one of the two words, "British" and "American." Nesting helps maintain the logic of the Boolean search and is often used when the terms have similar in meanings.
A wild card can be used when searching for alternate spellings. It usually replaces the letters within a word that has variable spellings. For example, "organiation" will generate results with the word "organization" (the American spelling) and "organization" (the British spelling.) Different search engines recognize various Boolean characters but the most common are the question mark (?), the asterisk () and the exclamation mark (!).
Databases store records by categorizing them in separate fields such as type of publication, year of publication, country, and publisher. You can limit your search by entering specific information and choosing a specific field to search on, if the database supports this option. Only the specified field will be searched for matching data and all other fields will be ignored.
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