Database Management Systems
Modern Database Management
12th Edition
Jeffrey A. Hoffer
Engr. Hina Iqbal
Lecturer CS
engr.hinaiqbal@gmail.com
© 2005 by Prentice Hall
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Course Learning Outcomes
At the end of the course students are expected
to:
BT Level PLO
PLO
Emphasis
1. Explain databases and distinguish different data
C2
models and business rules.
1
2
1. Apply Entity Relationship Data (ERD) model to
design databases after learning ERD.
C3
3
2
1. Formulate relational data model ERD model to
implement database.
C5
2
2
1. Analyze the relational database for different
anomalies.
C4
4
2
1. Write relational algebra expressions for
manipulating relations.
C2
1
2
2
Grading Policy for Theory
Assessment Items Theory
Assignments
Quizzes
Mid Exam (after 8 weeks)
Final examination (after 16 weeks)
Total
%age
10
10
30
50
100
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Books
• Modern Database Management Systems by Jeffery hoffer,
V. Ramesh, Heikki Topi.
• Reference Book:
• Database Systems: The Complete Book, 2nd Edition by
Hector Garcia-Molina, Jeffrey D. Ullman, Jennifer Widom
• Database Systems A Practical Approach to Design,
Implementation, and Management, 4th Edition, Thomas
Connolly, Carolyn Begg, Addison Wesley, 2005Android
Tutorial
• Fundamentals of Database Systems by R. Elmasri and S.
Navathe. 6th Edition, Addison-Wesley (2010). ISBN-10:
0136086209.
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Goal
• At the end of this course it is expected that
each student must be able to develop a
database System independently
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What is Data?
• Data are often viewed as the lowest level of abstraction
from which information and knowledge are derived.
• Raw data refers to a collection of numbers, characters,
images or other outputs from devices that collect
information to convert physical quantities into symbols,
that are unprocessed.
• Usually, there are many facts to describe something of
interest to us. (For example, employee data to calculate
payroll check, send company greetings, inform family
in case of emergency
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Data: Where can we find it?
Filing Cabinets
Spreadsheets
Paper piles
Folders
Memories
And many more …
Lists
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What is a Database?
• A database can be of any size and of varying
complexity.
• A software system that facilitates the creation and
maintenance and use of an electronic database
– For example, the list of names and addresses of friends
– The book catalog of a large library may contain half a
million records
– A database of much greater size and complexity is
maintained to keep track of the tax information filed by
taxpayers.
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Definitions
• Database: organized collection of logically related data
• Data: stored representations of meaningful objects and
events
– Structured: numbers, text, dates
– Unstructured: images, video, documents
• Information: data processed to increase knowledge in the
person using the data
• Metadata: data that describe the properties or
characteristics of end-user data and the context of those
data
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Figure 1-1a Data in context
Context helps users understand data
Figure 1-1b Summarized data
Graphical displays turn data into useful
information that managers can use for
decision making and interpretation
Descriptions of the properties or characteristics of the
data, including data types, field sizes, allowable
values, and data context
Disadvantages of File Processing
• Program-Data Dependence
– All programs maintain metadata for each file they use
• Duplication of Data
– Different systems/programs have separate copies of the same data
• Limited Data Sharing
– No centralized control of data
• Lengthy Development Times
– Programmers must design their own file formats
• Excessive Program Maintenance
– 80% of information systems budget
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Problems with Data Dependency
•
•
•
•
•
Each application programmer must maintain his/her
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
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Figure 1-3 Old file processing systems at Pine Valley
Furniture Company
Duplicate Data
Problems with Data Redundancy
• Waste of space to have duplicate data
• Causes more maintenance headaches
• The biggest problem:
– Data changes in one file could cause
inconsistencies
– Compromises in data integrity
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SOLUTION:
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)
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Database Management System
•
A software system that is used to create, maintain, and provide controlled
access to user databases
Order Filing
System
Invoicing
System
Payroll
System
DBMS
Central database
Contains employee,
order, inventory,
pricing, and
customer data
DBMS manages data resources like an operating system manages hardware resources
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What is a DBMS?
• Functions of DBMS
–
–
–
–
–
Insert records
Delete records
Update records
Query records
Add and Delete files from the database
• In short, DBMS comprises of two main parts
– Data Management in the database
– User Management associated with the database
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What is a DBMSs?
• Commercial DBMSs
Company
Product
Oracle
Oracle 8i, 9i, 10g,11i,11g,12c
IBM
DB2, Universal Server (from System
R, System R*, Starburst) & Informix
Microsoft
Access, SQL Server
Sybase
Adaptive Server
Informix
Dynamic Server
NCR
Teradata
UC Brekeley’s
INGRES,M PostgreSQL
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Advantages of the Database Approach
•
•
•
•
•
•
•
•
•
•
Program-data independence
Planned data redundancy
Improved data consistency
Improved data sharing
Increased application development productivity
Enforcement of standards
Improved data quality
Improved data accessibility and responsiveness
Reduced program maintenance
Improved decision support
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Costs and Risks of the Database Approach
• New, specialized personnel
• Installation and management cost and
complexity
• Conversion costs
• Need for explicit backup and recovery
• Organizational conflict
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Elements of the Database Approach
• Data models
– Graphical system capturing nature and relationship of data. capture the
nature of and relationships among data and are used at different levels
of abstraction as a database is conceptualized and designed. A data
model is a description of how data should be used to meet the
requirements given by the end user
– Enterprise Data Model – high-level entities and relationships for the
organization
– Physical Data Model – more detailed view, matching data structure in
database or data warehouse. Physical data models provide the
underlying structure of data from which queries are supported to
provide information to the enterprise. They are also used to identify
how the available data structures can be used to meet the information
requirements of the enterprise data model and to provide the basis
for developing interfaces between different computer systems.
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Elements of the Database Approach Cont ….
• Relational Databases
– Database technology involving tables (relations) representing
entities and primary/foreign keys representing relationships
• Use of Internet Technology
– Networks and telecommunications, distributed databases, clientserver, and 3-tier architectures
• Database Applications
– Application programs used to perform database activities (create,
read, update, and delete) for database users
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Segment of an Enterprise Data Model
Segment of a Project-Level Data Model
One customer
may place many
orders, but each
order is placed by
a single customer
 One-to-many
relationship
One order has
many order lines;
each order line is
associated with a
single order
 One-to-many
relationship
One product can
be in many
order lines, each
order line refers
to a single
product
 One-to-many
relationship
Therefore, one
order involves
many products
and one product is
involved in many
orders
 Many-to-many
relationship
Figure 1-5 Components of the Database Environment
Components of the
Database Environment
• CASE Tools – computer-aided software engineering CASE tools are
automated tools used to design databases and application programs.
These tools help with creation of data models and in some cases can
also help automatically generate the “code” needed to create the
database.
• Repository – centralized storehouse of metadata
• Database Management System (DBMS) –software for managing
the database
• Database – storehouse of the data
• Application Programs – software using the data
• User Interface – text and graphical displays to users
• Data/Database Administrators – personnel responsible for
maintaining the database
• System Developers – personnel responsible for designing databases
and software
• End Users – people who use the applications and databases
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Data Administrator
• Identified individual person in the organization who has
central repository of controlling data
• Job of data administrator is to decide
– What data should be stored in the database, identify the
entities of the interest to the organization
– Establishing policies for maintaining and dealing with that
data
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Database Administrator
• An individual or group of persons with an overview of
one or more databases who controls the design and use
of these databases
• Provides the necessary technical support for
implementing policy decisions of databases
• A DBA is the central controller of the database systems
who oversees and manages all the resources
• Responsible for authorizing access to the database, for
coordinating and monitoring its use and for acquiring
software and hardware resources as required
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Functions & Responsibilities of Database
Administrator
•
•
•
•
•
•
Defining conceptual schema and database creation
Storage structure and access-method definition
Granting authorization to the users
Physical organization modification
Routine maintenance
Job monitoring
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Database Users
• Users are differentiated by the way they expected to
interact with the system
• Application programmers
– Develop applications that interact with DBMS through
DML (Select, Insert, Update , Delete) calls
• Sophisticated users
– Form requests in a database query language
• End users
– Invoke one of the existing application programs (e.g.,
print monthly sales report)
– Interact with applications through GUI
– E.g. People accessing database over the web, bank
tellers, clerical staff
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The Range of Database Applications
•
•
•
•
•
Personal databases
Workgroup databases
Departmental/divisional databases
Enterprise database
Web-enabled databases
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Figure 1-6
Typical data
from a
personal
database
Figure 1-7 Workgroup database with wireless
local area network
Database Schema
• A schema is the structure behind data organization.
It is a visual representation of how different table
relationships enable the schema’s underlying mission
business rules for which the database is created.
• A database schema is a visual and logical architecture
of a database created on a database management
system.
• A database schema is a collection of metadata that
describes the relationships between objects and
information in a database.
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Two-Tier Architecture:
• The two-tier is based on Client Server architecture. The twotier architecture is like client server application. The direct
communication takes place between client and server. There
is no intermediate between client and server. Because of tight
coupling a 2 tiered application will run faster.
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•
The Two-tier architecture is divided into two parts:
1) Client Application (Client Tier)
2) Database (Data Tier)
On client application side the code is written for saving the data in the SQL server
database. Client sends the request to server and it process the request & send back
with data. The main problem of two tier architecture is the server cannot respond
multiple request same time, as a result it cause a data integrity issue.
• Advantages:
• Easy to maintain and modification is bit easy
• Communication is faster
• Disadvantages:
• In two tier architecture application performance will be degraded upon
increasing the users.
• Cost-ineffective
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Three-Tier Architecture:
• Three-tier architecture typically comprise
a presentation tier, a business or data access tier, and
a data tier. Three layers in the three tier architecture
are as follows:
1) Client layer 2) Business layer 3) Data layer
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1) Client layer:
It is also called as Presentation layer which contains UI part of our
application. This layer is used for the design purpose where data is
presented to the user or input is taken from the user. For example
designing registration form which contains text box, label, button
etc.
2) Business layer:
In this layer all business logic written like validation of data,
calculations, data insertion etc. This acts as a interface between
Client layer and Data Access Layer. This layer is also called the
intermediary layer helps to make communication faster between
client and data layer.
3) Data layer:
In this layer actual database comes in the picture. Data Access
Layer contains methods to connect with database and to perform
insert, update, delete, get data from database based on our input
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data.
Advantages
• High performance, lightweight persistent objects
• Scalability – Each tier can scale horizontally
• Performance – Because the Presentation tier can cache requests,
network utilization is minimized, and the load is reduced on the
Application and Data tiers.
• High degree of flexibility in deployment platform and
configuration
• Improve Data Integrity
• Improved Security – Client is not direct access to database.
• Easy to maintain and modification is bit easy, won’t affect other
modules
• In three tier architecture application performance is good.
Disadvantages
• Increase Complexity/Effort
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Enterprise Database Applications
• Enterprise Resource Planning (ERP)
– Integrate all enterprise functions (manufacturing,
finance, sales, marketing, inventory, accounting,
human resources)
• Data Warehouse
– Integrated decision support system derived from
various operational databases
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Figure 1-8 An enterprise data warehouse
Evolution of DB Systems
Data Abstraction
Database Systems provide users with an abstract
view of data hiding certain details of how data are
stored and maintained
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Data Abstraction
• Physical Level
– Describes how data is actually stored
• Logical Level
– Describes what data are stored in the database and what
relationships exist among those data
• View Level
– Describes only part of the entire database hiding details
of data types.
– Views can also hide information (e.g., salary) for
security purposes
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Level of Abstraction
Payroll
Inventory
Sales
Company database
Files on disks
Assignment No : 01
• Three Schema Architechure for Database
development
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THANK YOU
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