Fundamentals of Database Management Systems, Second Edition

CHAPTER 3

THE DATABASE MANAGEMENT SYSTEM CONCEPT

Data has always been the key component of information systems. In the beginning of the modern information systems era, data was stored in simple files. As companies became more and more dependent on their data for running their businesses, shortcomings in simple files became apparent. These shortcomings led to the development of the database management system concept, which provides a solid basis for the modern use of data in organizations of all descriptions.

OBJECTIVES

• Define data-related terms such as entity and attribute and storage-related terms such as field, record, and file.
• Identify the four basic operations performed on stored data.
• Compare sequential access of data with direct access of data.
• Discuss the problems encountered in a non-database information systems environment.
• List the five basic principles of the database concept.
• Describe how data can be considered to be a manageable resource.
• List the three problems created by data redundancy.
• Describe the nature of data redundancy among many files.
• Explain the relationship between data integration and data redundancy in one file.
• State the primary defining feature of a database management system.
• Explain why the ability to store multiple relationships is an important feature of the database approach.
• Explain why providing support for such control issues as data security, backup and recovery, and concurrency is an important feature of the database approach.
• Explain why ...