1. Database Fundamentals

2. Database Fundamentals
The term database refers to a collection of data that is multidimentional in the sense that internal links between its entries make the information accessable from a variety of perspectives. This is in contrast to a traditional file system, sometimes called a flat file, which is a one-dimentional storage system, meaning that it presents its information from a single point of view.

3. Database Fundamentals
Whereas a flat file containing information about composers and their compositions might provide a list of composition arranged by composer, a database might present all the works by a single composer, all the composers who wrote a particular type of music, and perhaps the composers who wrote variations of another composer’s work.

4. Database Fundamentals
the significance of database systems
Historically, as computing machinery found broader uses in information management, each application tended to be implemented as a separate system with its own collection of data. Payroll was processed using the payroll file, the personnel department maintained its own employee records, and inventory was managed via an inventory file.

5. Database Fundamentals
This meant that much of the information required by an organization was duplicated throughout the company, while many different but related items were stored in separate systems. In this setting, database systems emerged as a means of integrating the information stored and maintained by a particular organization (Figure 9.1).

6. Figure 9.1 A file versus a database organization

7. Database Fundamentals
Such integrated pools of information provided a valuable resource with which management decision could be made, assuming the information could be accessed in a meaningful way.

8. Database Fundamentals
Moreover, database systems have become the underlying technology that supports many of the more popular sites on the World Wide Web. The underlying theme of sites such as Google, eBay, and Amazon is to provide an interface between clients and databases. To respond to a client’s request, the server interrogates a database, organizes the results in the form of a Web page, and sends the page to the client.

9. to be continue…