1 O N E
In this chapter, you will learn:
½ The difference between data and information ½ What a database is, the various types of databases, and why they are valuable assets for decision making ½ The importance of database design ½ How modern databases evolved from file systems ½ About flaws in file system data management ½ The main components of the database system ½ The main functions of a database management system (DBMS)
Good decisions require good information that is derived from raw facts.These raw facts are known as data. Data are likely to be managed most efficiently when they are stored in a database. In this chapter, you will learn what a database is, what it does, and why it yields better results than other data management methods.You will also learn about various types of databases and why database design is so important. Databases evolved from computer file systems. Although file system data management is now largely outmoded, understanding the characteristics of file systems is important because file systems are the source of serious data management limitations. In this chapter, you will also learn how the database system approach helps eliminate most of the shortcomings of file system data management.
D A T A B A S E
S Y S T E M S
1.1 WHY DATABASES?
Imagine trying to operate a business without knowing who your customers are, what products you are selling, who is working for you, who owes you money, and whom you owe money. All businesses have to keep this type of data and much more; and just as importantly, they must have those data available to decision makers when they need them. It can be argued that the ultimate purpose of all business information systems is to help businesses use information as an organizational resource. At the heart of all of these systems are the collection, storage, aggregation, manipulation, dissemination, and management of data. Depending on the type of information...