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Database Design &
Management
Contents (Summary)
• Concepts of Database Management• Database Designing and Modelling• Client-Server Architecture, Data Dictionaries• SQL
– DDL,DML,Views ,Constraints• Oracle SQL• Distributed Database• Object oriented database• Database Administration
Method of Delivery
• Text Books
• Reference Book/s
• Lecture Slides
• Lab work (SQL)
• Helping notes or Reference website (email)
Key to success
• Punctuality
• Hard work
• Practice
• Devotion
• Dedication
Text Book
(1) Modern Database Management By:
Fred McFadden, Jeffrey Hoffer, Mary Prescott 5th Edition, Addison Wesley
(2) Database Systems Concepts By:
Silberschatz., Korth., Sudarshan 4th Edition
(3) Database Systems By:
Thomas Connolly, Carolyn Begg 3rd Edition
(4) An Introduction to Database Systems By:
C.J.Date
What is Data ?
Definition of Data
•Data consists of Facts, text, graphics, images, sound and video segments that have meaning to user’s environment.
•Data can exist in a variety of forms: - As numbers or text on pieces of paper - As bits and bytes stored in electronic memory - As facts stored in a person's mind.
Data Type
Data is what we measureData type refers to the classification of a particular type of information
• integer• floating point• character, string• date• student record• blob (binary large object)
Data in Context
Large volume of facts, difficult to interpret or make decisions based on
INFORMATION
• Data that has been processed in such a way that it can increase the knowledge of person who uses it
Useful information that managers can use for decision making and interpretation
Data vs Information
• Data into information–Summarise data
–Data In context (table)
–Decision support
• We use Database term without distinguish data or information
ACTIVITY
• Please write down the data for cricket match bowling
• Do you get any information??
Definition of Database
“ Database is a shared collection of logically related data, designed to meet the information needs of multiple users in an organization ”
Database is designed, built, and populated with data for a specific purpose. It has an intended group of users and preconceived applications in which these users are interested.
Alternative Terminology
Data Processing Terms
Formal Terms Alternative 1 Alternative 2
Relation Table File
Tuple Row Record
Attribute Column Field
• Formal terms are mostly used for technical users.• Data processing terms are more natural for non
technical users.
Computerized File Based Processing
System
Computerized File-based Processing
File handling routines & File definition
SalesSales files
File handling routines & File definition
ContractsContracts files
File-based Systems
• A collection of application programs that perform services for the end users (e.g. reports).
• Each program defines and manages its own data.
Three file processing systems
Duplicate Data
Limitation of Computerized File-based Approach
• Separation and Isolation of data• Each application maintains its own set of data. • Users of one application may be unaware of potentially
useful data held by other applications.Duplication of data (data redundancy)• Same data is held by different files.
Limited Data SharingNo centralized control of data
Lengthy Development TimesProgrammers must design their own file formats
Excessive Program Maintenance80% of information systems budget
Limitation of File-based Approach
• Accessibility• Data is stored using programs that are written in
different languages and format• Cannot easily access other files due to incompatible file
format.• No control over access and manipulation of data beyond
that imposed by application programs.• Hard Coded Queries (Data dependence)
• File structure and all definition of data are defined in the application program code.
• Programs are written to satisfy particular functions / requirements.
• Any new requirement needs a new program.
Problems with Data Dependency Each application programmer must maintain
their 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: – When data changes in one file, could
cause inconsistencies
– Compromises data integrity
Database Processing System
SOLUTION:SOLUTION:
Database Processing
Sales
ContractsApplication
Contracts
Database
SalesApplication
DBMS
The DATABASE Approach
• Central repository of shared data• Data is managed by a controlling
agent• Stored in a standardized, convenient
form
Requires a Database Management System (DBMS)
Database Management System
DBMS manages data resources like an operating system manages hardware resources
DBMSDBMS Databasecontainingcentralized
shared data
Application#1
Application#2
Application#3
Database Management System (DBMS)
A collection of programs that enables users to define,create and maintain and control access to the database.
General-purpose software system that facilitates the processes of defining, constructing and manipulating databases for various applications.
Defining - specifying data types, structures, constraints.Constructing - storing of dataManipulation - querying, updating and reporting.
Popular DBMS In The Market
Sybase SQL Anywhere
Informix Dynamic Server
Borland Interbase
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.
Advantages of Database Approach
• Program-Data Independence – Metadata stored in DBMS, so applications don’t need to
worry about data formats– Data queries/updates managed by DBMS so programs
don’t need to process data access routinesResults in: increased application development and
maintenance productivity
• Minimal Data Redundancy– Leads to increased data integrity/consistency
Advantages of Database Approach
• Improved Data Sharing– Different users get different views of the data
• Enforcement of Standards– All data access is done in the same way
• Improved Data Quality – Constraints, data validation rules
• Better Data Accessibility/ Responsiveness– Use of standard data query language (SQL)
• Security, Backup/Recovery, Concurrency– Disaster recovery is easier
Costs and Risks of the Database Approach
• Up-front costs:– Installation Management Cost and Complexity– Conversion Costs– Cost of DBMS– Additional hardware costs.
Ongoing Costs:– Requires New, Specialized Personnel– Need for Explicit Backup and Recovery– Higher impact of a failure
• Organizational Conflict:– Old habits die hard
The Range ofDatabase Applications
• Personal Database – standalone desktop database• Workgroup Database – local area network (<25 users)• Department Database – local area network (25-100
users)• Enterprise Database – wide-area network (hundreds
or thousands of users)
Personal Computer Database
Workgroup database with local area network
An enterprise data warehouse
Components of DBMS Environment
1. HardwareCan range from a PC to a network of computers.
2. SoftwareDBMS itself and operating system, including any network software if network is being used.
3. DataIncludes actual data used by the organization, and description of data (schema). Also a system catalog contains data such as the names of authorized users.
Components of DBMS Environment
4. ProceduresInstructions and rules that should be applied to the design and use of the database, and the use of the DBMS.
5. PeopleData & Database AdministratorDatabase Designer :- Logical & PhysicalApplication ProgrammersEnd Users
DBMS Environment
Software
Hardware
Procedures
People
Machine Human
Data
Bridge
Database System Environment
Users/Programs
Application Programs/Queries
Software to Process Queries/Programs
Software to Access Stored Data
Stored DatabaseDefinition
Stored Database
Evolution of DB Systems
• Flat files - 1960s - 1980s• Hierarchical – 1970s - 1990s• Network – 1970s - 1990s• Relational – 1980s - present• Object-oriented – 1990s - present• Object-relational – 1990s - present• Data warehousing – 1980s - present• Web-enabled – 1990s - present
Summary
• Course Contents• Data• Information• Data Vs Information• Database Terms• DBMS• Advantages• Disadvantages of DBMS • Database Terms• Comparison of Computerized File Based Processing
System & Database System