THE DATABASE MANAGEMENT SYSTEM CONCEPT - Fundamentals of Database Management Systems - page 58

137 Baker 10 1995

0121
0933
1047
1826

Main St. Hardware
ABC Home Stores
Acme Hardware Store
City Hardware

137
137
137
137

New York
Los Angeles
Los Angeles
New York

186 Adams 15 2001

0839
2267

Jane's Stores
Central Stores

186
186

Chicago
New York

204 Dickens 10 1998

2198 Western Hardware 204 New York

361 Carlyle 20 2001

F IGURE 3.10
General Hardware Company combined
files: One-to-many relationship vertical
variation

1525
1700

Fred's Tool Stores
XYZ Stores

361
361

Atlanta
Washington

particular, the way that the relational approach to database management handles it
will be explained in detail.

Data Control Issues
The people responsible for managing the data in an information systems environment
must be concerned with several data control issues . This is true regardless of which
database management system approach is in use. It is even true if no database
management system is in use, that is, if the data is merely stored in simple files.
Most prominent among these data control issues are data security, backup and
recovery, and concurrency control, Figure 3.11. These are introduced here and will
be covered in more depth later in this topic. The reason for considering these data
control issues in this discussion of the essence of the database management system

Security Backup and Recovery

F IGURE 3.11
Three data control issues

Concurrency Control