Introduction to Database Systems Answer Key 4th Edition
1． Describe the concepts of data, database, database system, and database management system.
answer:
(l) Data: Symbolic records describing things are called data. The types of data include numbers, text, graphics, images, sounds, text, etc. Data and its semantics are inseparable. The concept of parsing data in modern computer systems is broad. Early computer systems were mainly used for scientific calculations, and the data processed were integers, real numbers, floating point numbers and other traditional mathematics data.
Modern computers can store and process a wide range of objects, and the data representing these objects are becoming increasingly complex. Data and its semantics are inseparable. The number 500 can mean that the price of an item is 500 yuan, it can also mean that there are 500 people attending an academic conference, or it can mean that a bag of milk powder weighs 500 grams.
(2) Database (DataBase, referred to as DB): A database is an organized and shareable collection of data stored in a computer for a long time. The data in the database is organized, described and stored according to a certain data model. It has small redundancy, high data independence and easy scalability, and can be shared by various users.
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