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CHAPTER 1 – The Database Environment
Database – organized collection of logically related data
Data – stored representations of meaningful objects and events
Structured – numbers, text, dates
Unstructured – images, video, documents
Information – data processed to increase knowledge in the person using the data
Metadata – data that describes the properties and context of user data

Disadvantages of File Processing
Program-Data Dependence
- All programs maintain metadata for each file they use
Duplication of Data
- Different systems/programs have separate copies of the same data
Limited Data Sharing
- No centralized control of data
Lengthy Development Times
- Programmers must design their own file formats
Excessive Program Maintenance
- 80% of information systems budget

Problems with Data Dependency
- Each application programmer must maintain his/her own data
- Each application program needs to include code for the metadata of each file
- Each application program must have its own processing routines for reading, inserting, updating, and deleting data
- Lack of coordination and central control
- Non-standard file formats

Problems with Data Redundancy
- Waste of space to have duplicate data
- Causes more maintenance headaches
The biggest problem:
- Data changes in one file could cause inconsistencies
- Compromises in data integrity
SOLUTION:
The DATABASE Approach
- Central repository of shared data
- Data is managed by a controlling agent
- Stored in a standardized, convenient form
Database Management System
- A software system that is used to create, maintain, and provide controlled access to user databases
- DBMS manages data resources like an operating system manages hardware resources
Advantages of the Database Approach
- Program-data independence
- Planned data redundancy
- Improved data consistency
- Improved data

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