1. CS530: Databases

2. Objectives
Raise awareness about databases, database design and database management systems
Enable you to design and use a database to support an application
To understand the implications of your design
To realise that designing databases is non-trivial and requires imagination, flexibility and thought

3. Laboratory Exercise: Orinoco Records
Use, design and build a database to support a holiday booking system
Oracle 9i DBMS
Example classes and labs integrated

4. Course Materials Printed Material
Lecture Notes / Slides are Important and should be central to your revision
Associated Material is for background reading and is important for your understanding of the concepts (discussed in the lecture notes) in detail
Self Assessment Questions give you a weekly check on your progress
Mock Exams

5. Recommended Texts Primary - Warrender Secondary - Connolly and Begg
Databases (Computing Study Texts)
Secondary - Connolly and Begg
Database Systems
3rd Edition, Addison Wesley
Old but Valid - Elmasri and Navathe
Fundamentals of Database Systems
Lab – Earp and Bagui
Learning SQL (A Step by Step Guide Using Oracle)

6. Other Texts Atzeni, Ceri, Paraboschi and Torlone Ullman and Widom
Database Systems: Concepts, Languages an Architectures
MacGraw Hill
Ullman and Widom
A First Course in Databases
Garcia-Molina, Ullman and Widom
Database Systems: The Complete Book

7. Introduction

8. File Management Systems: a physical interface
Timetable
Student
Admin
Scheduler
Payroll
Data
Course
Lecturer
Year List
Cheques
Student info processed to year lists
Course data -> scheduler -> timetable
Lecturer data -> payroll -> cheques

9. File Management Systems: Sharing
Timetable
Student
Admin
Scheduler
Payroll
Data
Course
Lecturer
Year List
Cheques
Easy to see need to share between physical data stores to perform more sophisticated processes

10. F M S: Replication and Redundancy
Timetable
Student
Admin
Scheduler
Payroll
Year List
Cheques
Students
Course Data
Lecturer Data

11. File Management Systems
Uncontrolled redundancy
Inconsistent data
Inflexibility
Limited data sharing
Poor enforcement of standards
Low programmer productivity
Excessive program maintenance
Excessive data maintenance

12. DBMS: A Logical Interface
University
Database Metadata
student
course
lecturer
Database
Mgmt
System
Lab
Timetable
University Database
Data
Data Dictionary or
System Catalog
?QUERIES
Teaching
Schedule
Tutorials
All data in one place and processes all via dbms data dictionary
Queries against dbms

13. What is a database? a structured collection of information
captures the semantics of an application
Logically coherent—so it makes sense
Inherent meaning—information vs data
Specific purpose—intended user group
Representation of the real world—changes in the real world reflected in the database

14. Database Management Systems?
a collection of programs and tools to create & maintain a database
Defining specifying types of data
Constructing storing & populating
Manipulating querying, updating, reporting

15. Characteristics of a Database
Structure
data types
data behaviour
Persistence
store data on secondary storage
Retrieval
a declarative query language
a procedural database programming language
Performance
retrieve and store data quickly Correctness
Sharing
concurrency
Reliability and resilience
Large volumes

16. DbMS Approach Controlled redundancy
consistency of data & integrity constraints
Integration of data
self-contained & represents semantics of application
Data and operation sharing
multiple interfaces
Services & Controls
security & privacy controls
backup & recovery
enforcement of standards
Flexibility
data independence
data accessibility
reduced program maintenance
Ease of application development

17. Continued more expensive more complex general simple
stringent real-time
single user
static
Summary:
In a file management system its data is PHYSICALLY accessed and UNINTEGRATED
In a database management system data is LOGICALLY accessed and INTEGRATED
a data dictionary
a query language

18. Actors Database Administrator DBA Designers End Users
Casual
‘parametric’
or ‘canned’ transactions
sophisticated
Database Management System
DBMS Designers and Implementers
Tool Developers
Operators and Maintenance
Personnel
Outer box: dbms – designers, tool de elopers, operators, maintenance personnel
Inner box: databases – end users, administrators, designers

19. Simplified Environment (from Elmasri & Navathe)
DBMS Software
Application Programs/Queries
Users/Programmers
Software to Process Queries / Programs
Software to Access Stored Data
Database System
Stored Database Definition
(Metadata)
Stored
Database
Waterfall view
Top: users/programmers
Big box:
Applications
DBMS softwqre: query processing, data bccesss
Database definition (metadata) and data itself

20. Interfaces to a Data Dictionary
Database
Application
End Users
Administrators
Programmers
Human Interfaces
Data Dictionary
Software and
DBMS Interfaces
Integrity
Compilers /
Application Programs /
Both humans and software have use and view on data dictionary
Integrity, query processing, etc for software
Data entry, and query formulation by humans
Constraint
Precompilers
Report Generators
Enforcer

21. Models and Schemas Model Data Model
A structure that demonstrates all the required features of the parts of the real world which is of interest to the users of the information in the model.
Representation and reflection of the real world (Universe of Discourse)
Data Model
A set of concepts that can be used to describe the structure of a database: the data types, relationships, constraints, semantics and operational behaviour.
It is a tool for data abstraction
A model is described by the schema which is held in the data dictionary.
Student(studno,name,address)
Course(courseno,lecturer)
Student(123,Bloggs,Woolton)
(321,Jones,Owens)
Schema
Instance

22. Sharing—Multiple views of data
DataBase Management System
Database
Different users (human and printers (for instance)) have access to and different views on data

23. Data Independence Logical data independence Physical data independence
Database
New
hardware
New functions
users
New storage
techniques
Linkage to other
databases
New data
User's
view
Change in
use
technology
Logical data independence
change the conceptual schema without having to change the external schemas
Physical data independence
change the internal schema without having to change the conceptual schema
Logical
Conceptual schema
External schema
Independent of change aat various levels

24. Ansi-Sparc Database Architecture
Conceptual Schema
Conceptual Level
Internal schema
Internal Level
External Level
External
View A
View B
View N
external/conceptual mapping
conceptual/internal mapping
End Users
Stored Database
Users
Various views
Conceptual schema
Internal schema
Database cans

25. For Next Lecture Re-Read These Notes Prep for Lab 1 – Systems Training
I expect you to have SKIM Read the notes for the next lecture before it’s delivered. The sequence of: skim read; lecture delivery; SAQ will make revision a whole lot easier.

26. Additional Information
Enclosed
Syllabus
Course Schedule
Course Overview
Other
Chapter 1
R.L. Warrender, Databases (Computing Study Texts), ISBN:
Chapter 0
Earp, Bagui, Learning Sql:a Step-by-Step Guide Using Oracle.
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