Itec50 – Database Management System
CHAPTER 1
THE DATABASE ENVIRONMENT
At the end of this chapter, the student should be able to:
1. Identify the five categories of databases and several key decisions that must be made for each category;
2. Briefly describe the evolution of a database systems; and
3. List and briefly discuss the components of a typical database environment;
Basic Concepts and Definition
Database – An organized collection of logically related data.
Data – stored representations of objects and events that have meaning and importance in the user’s environment.
Structured data –
Example of structured data: customer name, address and telephone number.
Ex. Of structured data type: numeric, character and dates.
Unstructured Data/ Multimedia Data –
Example of unstructured data: video, sounds, photographic images, documents,
Maps.
Data Versus Information
Information – data that have been processed in such a way as to increase the knowledge of the person who uses the data.
Data
Baker, Kenneth D
Doyle, Joan E.
Finkle, Clive R.
Lewis, John C.
McFerran, Debra R.
Sisneros, Michael
324917628
476193248
548429344
551742186
409723145
392416582
Converting data to information
A. Data in context
1 - aves
Class Roster
Course: MGT 500
Business Policy
Section: 2
Name
Baker, Kenneth D
Doyle, Joan E.
Finkle, Clive R.
Lewis, John C.
McFerran, Debra R.
Sisneros, Michael
Semester: Spring 2009
ID
324917628
476193248
548429344
551742186
409723145
392416582
Major
MGT
MKT
PRM
MGT
IS
ACCT
GPA
2.9
3.4
2.8
3.7
2.9
3.3
Itec50 – Database Management System
B. Summarized Data
GPA
Baker, Kenneth D
324917628 MGT
Doyle, Joan E.
476193248 MKT
Finkle, Clive R.
548429344 PRM
Lewis, John C.
551742186 MGT
McFerran, Debra
R. 409723145 IS
Sisneros, Michael
392416582
ACCT
Metadata – Data that describe the properties or characteristics of end-user data, and the context of that data. Some of the
properties that are typically described include data names, definitions, length (or size), and allowable values. Metadata describing
data context include the source of the data, where the data are stored, ownership and usage.
Example Metadata for Class Roster
Data Item
Name
Course
Section
Semester
Name
ID
Major
GPA
Type
Alphanumeric
Integer
Alphanumeric
Alphanumeric
Integer
Alphanumeric
Decimal
Length
30
1
10
30
9
4
3
Min
Value
Max
1
9
0.0
4.0
Description
Course ID & name
Section number
Semester & year
Student Name
Student ID (SSN)
Student Major
Student grade point
average
Source
Academic Unit
Registrar
Registrar
Student IS
Student IS
Student IS
Academic Unit
Database Management Systems
A software system that is used to create, maintain, and provide controlled access to user databases.
Data Models
Graphical systems used to capture the nature and relationships among data. Data models are created at both the
enterprise and project levels.
Enterprise data model – a graphical model that shows the high-level entities for the organization and the relationships among those
entities.
Project-level data model – more detailed and more closely match the way a database and applications against it.
2 - aves
Itec50 – Database Management System
Comparison of Enterprise and project level data models
Segment of an enterprise data model
CUSTOMER
Places
Segment of a project data model
CUSTOMER
Customer_ID
PRODUCT
Product_ID
Customer_Name
Standard_Price
Places
has
Is placed by
ORDER
Contains
Is placed by
ORDER
Order_ID
Order_Date
Contains
Is contained in
Is for
ORDER
LINE
Quantity
Is contained in
PRODUCT
Entity – a person, place, object, event, or concept in the user environment about which the organization wishes to main data.
CUSTOMER and ORDER are entities. Each customer’s information is referred to as an instance of CUSTOMER.
Relational database – a database that represents data as a collection of tables in which all data relationships are represented by
common values in related tables.
TRADITIONAL FILE PROCESSING SYSTEM
Disadvantages of File Processing System
1. Program-data dependence
2. Duplication of Data
3. Limited data sharing
4. Lengthy development times
5. Excessive program maintenance
Database Application: An application program (or set of related programs) that is used to perform a series of database activities (
create, read, update, and delete) on behalf of database users.
Advantages of the Database Approach
1. Program-data independence
2. Planned data redundancy
3. improved data consistency
4. improved data sharing
5. increased productivity of application development
6. enforcement of standards
7. improved data quality
8. improved data accessibility and responsiveness
9. reduced program maintenance
10. improved decision support
3 - aves
Itec50 – Database Management System
Data independence –the separation of data description from the application programs that used the data
User View – a logical description of some portion of the database that I required by a user to perform some task.
COST AND RISKS OF THE DATABASE APPROACH
1.
2.
3.
4.
5.
New, specialized personnel
Installation and management cost and complexity
Conversion costs
need for explicit backup and recovery
organization conflict
COMPONENTS OF THE DATABASE ENVIRONMENT
Data and database
administrators
Application
programs
System
developers
USER
INTERFACE
End
users
Application
programs
DBMS
REPOSITORY
1.
2.
3.
4.
5.
6.
7.
8.
9.
Computer-aided software engineering (CASE) tools
Repository
DBMS
Database
Application programs
User Interface
Data and Database Administrators
System Developers
End Users
4 - aves
Database
Itec50 – Database Management System
RANGE OF DATABASE APPLICATIONS
5 Categories
1.
Personal Database - designed to support one user.
2.
Workgroup database – a relatively small team of people who collaborate on the same project or application or on a
group of similar projects or applications.
3.
Departmental / divisional database- generally larger than a workgroup. Designed to support the various functions and
activities of a department or division.
4.
Enterprise Databases- one whose scope is the entire organization or enterprise. Such databases are intended to
support organization wide operations and decision making.
2 Major Developments
1. Enterprise resource planning (ERP) systems
- a business management system that integrates all functions of the enterprise, such as
manufacturing, sale, finance, marketing, inventory, accounting, and human resources. ERP systems are software
applications that provide the data necessary for the enterprise to examine and manage its activities
2. Data warehousing implementations
- an integrated decision support database whose content is derived from the various operational
databases.
5.
Web-enabled databases
Summary of Database Applications
Types of Database
Personal
Typical Number of Users
1
Workgroup
Department/ Division
Enterprise
5-25
25-100
>100
Web-enabled
>1000
Typical Architecture
Desktop/laptop
computer, PDA
Client/server (two-tier)
Client/server (three-tier)
Client/server (distributed
or parallel server)
Web server and
application servers
HISTORY OF DATABASE SYSTEMS

1950s and early 1960s:
o Data processing using magnetic tapes for storage
 Tapes provide only sequential access
o Punched cards for input

Late 1960s and 1970s:
o Hard disks allow direct access to data
o Network and hierarchical data models in widespread use
o Ted Codd defines the relational data model
 Would win the ACM Turing Award for this work
 IBM Research begins System R prototype
 UC Berkeley begins Ingres prototype
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Typical Size of Database
Megabytes
Megabytes-gigabytes
Gigabytes
Gigabytes-terabytes
Megabytes-gigabytes
Itec50 – Database Management System
o
High-performance (for the era) transaction processing

1980s:
o Research relational prototypes evolve into commercial systems
 SQL becomes industry standard
o Parallel and distributed database systems
o Object-oriented database systems

1990s:
o Large decision support and data-mining applications
o Large multi-terabyte data warehouses
o Emergence of Web commerce

2000s:
o
o
o
o
6 - aves
XML and XQuery standards
Automated database administration
Increasing use of highly parallel database systems
Web-scale distributed data storage systems