IVE Database
Chapter 1 - Database Concepts and Architecture
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Chapter 1 -
Database Concepts
1. Topics
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Definitions
Disadvantages of File Processing
Database Management System
Advantages of the Database Approach
Costs and Risks of the Database Approach
The Range of Database Application
2. Definitions
a) Data:
Meaningful facts, text, graphics, images, sound, video segments.
Data in Context
b) Database:
An organized collection of logically related data.
c) Information:
Data processed to be useful in decision making.
3. Disadvantages of File Processing Systems
a) Data Dependence
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b) Data Redundancy (Duplication of data)
c) Limited Data Sharing
d) Lengthy Development Times
e) Excessive Program Maintenance
4. Database Management System
A DBMS is a data storage and retrieval system which permits data to be stored non-redundantly
while making it appear to the user as if the data is well-integrated.
5. Advantages of the Database Approach
a) Program-Data Independence:
The separation of data descriptions (metadata) from the application programs that use the
data is called data independence. This property of database systems allows an
organization's data to change and evolve (within limits) without changing the application
programs that process the data.
b) Minimal Data Redundancy
The design goal with the database approach is that previously separate (and redundant) data
files are integrated into a single, logical structure. Each primary fact is recorded (ideally)
in only one place in the database. For example, the fact that the product with Product_ID 3
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is an oak computer desk with a unit price of $375.00 is recorded in one place in the Product
table.
c) Improved Data Consistency
By eliminating (or controlling) data redundancy, we greatly reduce the opportunities for
inconsistency. For example, if a customer address is stored only once, we cannot have
disagreement on the stored values.
d) Improved Data Sharing
A database is designed as a shared corporate resource. Authorized users are granted
permission to use the database, and each user (or group users) is provided one or more user
views to facilitate this use.
e) Increased Productivity of Application Development
A major of the database approach is that it greatly reduces the cost and time for developing
new business applications.
f) Enforcement of Standards
When the database approach is implemented with full management support, the database
administration function should be granted single-point authority and responsibility for
establishing and enforcing data standards.
g) Improved Data Quality
The database approach provides a number of tools and processes to improve data quality.
h) Improved Data Accessibility and Responsiveness
With a relational database, end users without programming experience can often retrieve and
display data, even when it crosses traditional departmental boundaries.
i) Reduced Program Maintenance
Stored data must be changed frequently for a variety of reasons: new data item types are
added, data formats are changed, and so on. In a database environment, data are more
independent of the application programs that use them. Within limits, we can change
either the data or the application programs that use the data without necessitating a change in
the other factor. As a result, program maintenance can be significantly reduced in a
modern database environment.
6.
Database Applications
a)
Personal Database
Designed to support one user with a standalone personal computer (for example, a
desktop or laptop computer).
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b)
Workgroup Database
A workgroup is a relatively small team of people who collaborate on the same project
or application or a group of similar projects or applications. A workgroup typically
comprises fewer than 25 persons. A workgroup database is designed to support the
collaborative efforts of such a team.
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c)
Department Database
A department is a functional unit within an organization. Typical examples of
departments are personnel, marketing, and accounting.
Department databases are designed to support the various functions and activities of a
department.
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d)
Enterprise Database
An enterprise database is one whose scope is the entire organization or enterprise (or, at
least, many different departments). Such databases are intended to support
organization-wide operations and decision making.
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