If you are looking for information, library shelves are a good place to start. But if you need up-to-the-minute data or have specialized needs, you may find a computerized database more useful, less expensive, and less time 11 .A database, a file of information on one subject or family of subjects, can be stored and 12 in a computer's memory. The speed of the computer then 13 you to recall any item in this file almost 14
The three main types of databases are statistical, bibliographic, and full text. Statistical databases store 15 amounts of numerical data, such as wage and price indexes, census information, foreign 16 rates and bond prices. Bibliographic databases store references to and summaries of articles in periodicals and newspapers. Full-text databases offer the complex texts of such 17 as newspaper, magazine, and journal articles.
Thousands of databases exist today, and their numbers are growing. Many companies have their in-house database, which is 18 to employees through computer terminals or microcomputers. In addition, several hundred commercial databases are now available to the 19 , with literally millions of items of information readily obtainable. These databases 20 specific fields, such as law and financial forecasting, or general information, such as sports and weather data.来源：http://www.hxen.com
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