Unit Seven Database 1.Passage One. Foundation of Database

Training target: In this part ， our target is to train your reading comprehension. We have made the flexible sentences strong black and marked the subject ， predicate and object of them. Try to grasp the main idea of these sentences.

Text 1.Database System Application. Database System is now used in various aspects of society ， such as government apparatus ， universities ， airlines ， banking ， telecommunication and manufacturing. In government apparatus ， database can be used to know information resources of human affairs and carders in various aspects as well. In banking ， database can be used for customer information ， accounts ， loans ， and banking transactions. In airlines ， database can be used for reservations and schedule information. In universities ， database can be used for student information ， course registrations and grades.

In the management of economy ， database can proceed at statistic data and analysis ， and obtain a result so as to guide the enterprises to develop rapidly. Previously ， very few people interacted directly with the database system. Till the late1990s ， the assessment to database for users increased with the development of Internet work. For example ， when you access a network station and look through the contents on it ， in fact ， you are accessing the data stored in database. When you access an online shopping website ， information about your order for goods may be retrieved from a database. Database plays an important role in most enterprises today.

（ 1 ） Data: Data are a collection of facts made up of numbers ， characters and symbols ， stored on a computer in such a way that the computer can process it. Data are different from information in that they are formed of facts stored in machine readable form. When the facts are processed by the computer into a form ， which can be understood by people ， the data become information. 2.Basic Database Conceptions

（ 2 ） Database: Database is a collection of related objects ， including tables ， forms ， reports ， queries ， and scripts ， created and organized by a database management system （ DBMS ）. A database can contain information of almost any type ， such as a list of magazine subscribers ， personal data on the space shuttle astronauts ， or a collection of graphical images and video clips.

 （ 3 ） Database management system: Data management system is a software that controls the data in a database ， including overall organization ， storage ， retrieval ， security ， and data integrity. A DBMS can also format reports for printed output and can import and export data from other application using standard file formats. A data manipulation language is usually provided to support database queries.

（ 4 ） Database model: Database model is the method used by a database management system （ DBMS ） to organize the structure of the database. The most common database model is the relational database.

（ 5 ） Database server: It is any database application that follows the client. server architecture model ， which divides the application into two parts: a frontˉend running on the user’s workstation and backˉend running on a server or host computer. The frontˉend interacts with the user ， collects and displays the data. The backˉend performs all the computer intensive tasks ， including data analysis ， storage ， and manipulation.

（ 6 ） Relational Database: Relational database is a database model in which the data always appear from the point of view of the user to be a set of twoˉdimensional tables ， with the data presented in rows and columns. The rows in a table represent records ， which are collections of information about a specific topic ， such as the entries in a doctor’s patient list. The columns represent fields ， which are the items that make up a record ， such as the name ， address ， city ， state ， and zip code in an address list database. Pic 3.1

 The End