3902 Chapter 1

1

• Outline Introduction
• What is a database?
• The main characters of a database system
• The basic database design method
• The entity-relationship data model for
  application modeling

2

• Types of databases
• traditional
• multimedia - pictures, video, sound
• Scientific database
• - GIS maps, weather, satellite images
• - biological database DNA sequence analysis
• warehouse, OLAP - analysis, decision making
• real-time, active databases - industrial
  processes

3

• Database
• collection of related data
• represents some aspect of the real world
• logically coherent collection
• built with a specific purpose in mind
• could be anywhere - notebook, spreadsheet,
  Access, Oracle, could be manual / could be
  computerized
• Data
• known and recordable facts
• name, phone number, address, grade, ...

4

• Database Management System (DBMS)
• collection of software facilitating the
  definition,
• construction and manipulation of databases

• Definition
• record structure
• data elements
• names
• data types
• constraints
• etc

• Manipulation
• querying
• updating

• Construction
• create database
• files
• populate the
• database with
• records

5

• Database Management System (DBMS)
• collection of software facilitating the
  definition, construction and manipulation of
  databases

DBMS
Meta data
Request manager
Storage manager
Stored database
Users/actors
6
(No Transcript)
7

• Characteristics of the Database approach
• single repository of data
• sharable by multiple users
• concurrency control
• transaction control
• self-describing - system catalogue contains meta
  data
• program-data independence
• some changes to the database are transparent to
• programs/users
• multiple views of data - to support individual
  needs of programs/users

8

• Database Actors
• Database Administrator (DBA) - authorizing
  access to the database - coordinating and
  monitoring its use - aquiring software and
  hardware as needed - solving problems such as
  breach of security or poor system performance
• Database Designers/Modelers - identifying the
  data to be stored - choosing appropriate data
  structure
• End-users - access to the database
  querying, updating, generating reports
• Software Engineers - developing application
  programs

9

• Advantages of the Database approach
• (capabilities we would look for in a DBMS)
• controlled redundancy
• database design integrates different user data
  needs
• performance tuning may lead to replicated data
• controlled/authorized access to data
• SQL Grant and Revoke commands
• enforcing integrity constraints
• intra-record constraints e.g. data type,
  netltgross
• inter-record constraints StNo in Grades exists
  as a StNo in Student
• backup and recovery

10

• Implications of the Database approach
• standards enforcement
• DBA can enforce standard naming conventions, etc
• reduced application development time
• adding new functionality to an existing database
  is
• easy
• flexibility
• adding new data and making some types of changes
  is easy
• up-to-date information - due to sharable
  characteristic
• economies of scale - due to sharable resources
  the whole
• organization can make one investment

11

• When not to use a DBMS
• overhead costs are too great
• high initial investment
• generality
• overhead of security, concurrency control,
  recovery, integrity
• data and applications are simple, well-defined,
  not expected to change
• stringent real-time constraints
• multi-user environment not needed

12

• Database design
• lets jump ahead to see this
• ERDs are covered in Chapter 3

Course
1
Student
Delivery
N
M
Grades
Section
N
13

• Database design
• lets jump ahead to see this
• ERDs are covered in Chapter 3

Course
StNo
1
Student
Class
Delivery
Major
Name
N
M
Grades
Section
N
14

• Database design
• lets jump ahead to see this
• ERDs are covered in Chapter 3

CNo
CrHrs
Dept
Course
CName
StNo
1
Student
Class
Delivery
Major
Name
N
M
Grades
Section
N
15

• Database design
• lets jump ahead to see this
• ERDs are covered in Chapter 3

CNo
CrHrs
Dept
Course
CName
StNo
1
Student
Class
Delivery
Major
Name
N
M
Semester
Grades
Section
N
Year
SId
Instructor
16

• Database design
• lets jump ahead to see this
• ERDs are covered in Chapter 3

CNo
CrHrs
Dept
Course
CName
StNo
1
Student
Class
Delivery
Major
Name
N
M
Semester
Grades
Section
N
Year
grade
SId
Instructor