Software Design and Architecture. -2.ppt

Database Design
&
Management
Objectives of this lecture:
The meaning of the term database
The Characteristics of DB approach
The benefits with DB approach
Clearly understand the different types of database.
Understand the client/server Architecture
Discuss the different components of DBMS
environment.

Definition of Database
“ Database is a shared collection of logically
Database is a shared collection of logically
related data, designed to meet the
related data, designed to meet the
information needs of multiple users in an
information needs of multiple users in an
organization
organization ”
Database is designed, built, and populated
Database is designed, built, and populated
with data for a specific purpose. It has an
with data for a specific purpose. It has an
intended group of users and preconceived
intended group of users and preconceived
applications in which these users are
applications in which these users are
interested.
interested.

What is a Database …
What is a Database …
A brief definition is
A brief definition is
For performing daily operational & Administrative
For performing daily operational & Administrative
tasks.
tasks.
For later observations & analysis.
For later observations & analysis.
Using some storage device like HDD, Cartridge disk,
Using some storage device like HDD, Cartridge disk,
Compact Disk, Tape Devices.
Compact Disk, Tape Devices.
An organized store of information
An organized store of information.
.
Held over a period of time.
Held over a period of time.
In computer readable form.
In computer readable form.

D
Database
atabase
characteristics
characteristics
and
and
advantages
advantages
Minimal duplications
of data
File sharing
Easy data retrieval

The Range of
Database 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
Personal
Computer
Computer
Database
Database

Workgroup database with local area network
Workgroup database with local area network

An
An
enterprise
enterprise
data
data
warehouse
warehouse

Types of Database
There are different types of databases according
to:
(1)Function / Purpose of database
(2)Location of database
(3)Model of database
(4)Architecture of database

Analytic Databases
Analytic databases (a.k.a. OLAP- On Line Analytical
Processing) are primarily static, read-only databases
which store archived, historical data used for analysis. For
example, a company might store sales records over the
last ten years in an analytic database and use that
database to analyze marketing strategies in relationship
to demographics.
• On the web,analytic databases in the form of inventory
catalogs such as Amazon.com. An inventory catalog
analytical database usually holds descriptive information
about all available products in the inventory.
• Web pages are generated dynamically by querying the list
of available products in the inventory against some search
parameters. The dynamically-generated page will display
the information about each item (such as title, author,
ISBN) which is stored in the database.

Operational Databases
• Operational databases (a.k.a. OLTP On Line
Transaction Processing), on the other hand, are used to
manage more dynamic bits of data. These types of
databases allow you to do more than simply view
archived data. Operational databases allow you to
modify that data (add, change or delete data).
• These types of databases are usually used to track real-
time information.
• For example, a company might have an operational
database used to track warehouse/stock quantities. As
customers order products from an online web store, an
operational database can be used to keep track of how
many items have been sold and when the company will
need to reorder stock.

Types of Database
• Centralized
Database
• Personal Computer
Database.
• Multi user Database
• Distributed
Database
• Homogenous.
• Heterogenous.

Corporate Computing Model.
Corporate Computing Model.
Each terminal has its own database.
Each terminal has its own database.
No sharing of data.
No sharing of data.
Stand alone
Stand alone

Multi-User DBMS Architectures
• Client-server
- Teleprocessing
- File Server
- Database Server

What is “Client/Server”
• “Client/server” is sometimes used to
refer to processes (clients) that request
services of other processes (servers) –
these processes may execute either on
the same or different computers
• However, “client/server database”
generally implies that the processes
execute on different machines

Client/Server Architecture
• A client/server system (whether database
oriented or not) can be thought of as having
three main software components:
– A front end application (resident at the client
and with which the user interacts)
– A back end application (resident on the server
and which services the client requests)
– Communication middleware

Network
R
e
q
u
e
s
t
Result
Elements of C-S Computing
Elements of C-S Computing
a client, a server, and network
a client, a server, and network
Client
Server
Client machine
Server machine

Application Tasks
User Interface
Presentation Logic
Application Logic
Data Requests & Results
Physical Data Management

Teleprocessing
• Traditional architecture.
• Single mainframe with a number of
terminals attached.
• Trend is now towards downsizing.

Presentation Logic
Application Logic
DBMS
Client
Server
Network
K
e
y
s
t
r
o
k
e
Displays
Client (dumb) - Server Model
Client (dumb) - Server Model

File-Server
• File-server is connected to several workstations across a
network.
• Database resides on file-server.
• DBMS and applications run on each workstation.
• Disadvantages include:
– Significant network traffic.
– Copy of DBMS on each workstation.
– Concurrency, recovery and integrity control more complex.

File Server Database Systems
Database
Operating
System
Client Server
Fully
Functional
DBMS
File requests,
Updated whole files
Whole files

Database-Server
• Server holds the database and the DBMS.
• Client manages user interface and runs
applications.
• Advantages include:
– wider access to existing databases;
– increased performance;
– possible reduction in hardware costs;
– reduction in communication costs;
– increased consistency.

Database Server Systems
Database
Full-fledged
DBMS
Client Server
Application
Program
SQL
Required record(s)

Database-Server Model
Presentation Logic
Client
Server
Network
K
e
y
s
t
r
o
k
e
Processed
Results
Application Logic
DBMS

More About Client/Server …
Types of Client/Server
One Server – One Client
One Server – One Client
Server
Server
One Server – many clients
One Server – many clients
Client 2
Client 2
Client 3
Client 3
Client 1
Client 1
Server
Server

Many Servers – Many Clients
Many Servers – Many Clients
Client &
Client &
Server
Server
Client &
Client &
Server
Server
Client &
Client &
Server
Server

Database Schema
Database Schema
The description of the database is called
The description of the database is called
database schema. A database schema is
database schema. A database schema is
describe during database design and not
describe during database design and not
expected to change frequently.
expected to change frequently.
Schema Diagram
Schema Diagram
Displayed schema is called schema diagram.
Displayed schema is called schema diagram.
Each object in schema is called a schema
Each object in schema is called a schema
construct.
construct.

Database instance (occurrence or state)
Database instance (occurrence or state)
The data in a database at a particular
The data in a database at a particular
moment of time.
moment of time.
Intension & Extension
Intension & Extension
The schema is sometimes called the
The schema is sometimes called the
intension and a database instance is called
intension and a database instance is called
an extension of the schema.
an extension of the schema.

Database Languages
Database Languages
Used to specify the conceptual schema
Used to specify the conceptual schema
Used to specify the internal schema
Used to specify the internal schema
Used to specify the external schema
Used to specify the external schema
Used for manipulation of data, like retrieval,
Used for manipulation of data, like retrieval,
insertion, deletion and modification.
insertion, deletion and modification.
Data Definition Language (DDL)
Data Definition Language (DDL)
Storage Definition Language (SDL)
Storage Definition Language (SDL)
View Definition Language (VDL)
View Definition Language (VDL)
Data Manipulation Language (DML)
Data Manipulation Language (DML)

Host Language
Host Language
Data sub-language
Data sub-language
A general purpose programming language,
A general purpose programming language,
providing various non-database facilities, such
providing various non-database facilities, such
as variables declarations, computational
as variables declarations, computational
operators, logic construct and so on.
operators, logic construct and so on.
For example: C, C++, VBA, COBOL
For example: C, C++, VBA, COBOL
Embedded language within the host language.
Embedded language within the host language.
For example: SQL can be used as standalone
For example: SQL can be used as standalone
language and also as embedded in C or VB.
language and also as embedded in C or VB.

Possible databases
• Personal address book
• a collection of documents
• a collection of excel
spreadsheets
• data, collected, maintained and
used somewhere

Components of the
Database Environment
• CASE Tools:
computer-aided software engineering
• Repository:
centralized storehouse of metadata
DBMS Operational environment is an
DBMS Operational environment is an
integrated system of hardware, software and
integrated system of hardware, software and
people that is designed to facilitate the
people that is designed to facilitate the
storage , retrieval and control of the
storage , retrieval and control of the
information resources and to improve the
information resources and to improve the
productivity of the organization.
productivity of the organization.

Components of the Database Environment
• Application Programs:
software using the data
• User Interface:
text and graphical displays to users
Database Management System:
Database Management System:
software for managing the database
software for managing the database
Database:
Database:
storehouse of the data
storehouse of the data

Components of the Database Environment
• System Developers :
personnel responsible for designing
databases and software
• End Users:
people who use the applications and
databases
Data Administrators:
Data Administrators:
personnel responsible for maintaining the
personnel responsible for maintaining the
database
database

Components of the database environment
Components of the database environment

Database System
Environment
Users/Programs
Application Programs/Queries
Software to Process
Queries/Programs
Software to Access Stored Data
Stored Database
Stored Database
Definition
Definition
Stored
Stored
Database
Database

Database Components
DBMS
===============
Design tools
Table Creation
Form Creation
Query Creation
Report Creation
Procedural
language
compiler (4GL)
=============
Run time
Form processor
Query processor
Report Writer
Language Run time
User
Interface
Applications
Application
Programs
Database
Database contains:
User’s Data
Metadata
Indexes
Application Metadata

CASE Tools:
• Purpose –
• To support the efficient and effective
development of database applications.
• CASE support may include
– A data dictionary to store information about
the database application’s data.
– Design tools to support data analysis.
– Tools to develop the corporate, conceptual,
and logical data models.
– Tools to enable the prototyping of applications.

Divided into three categories:
• upper-CASE,
• lower-CASE, and
• integrated-CASE.
Can provide the following benefits
• – Standards
• – Integration
• – Support for standard methods
• – Consistency
• – Automation

Database Application Lifecycle – CASE Tools

System Catalog
A repository of information (meta-data)
describing, formally, the data in the database.
Also sometimes called a data dictionary.
• Typically stores:
• – Names of authorized users.
• – Names of data items in the database.
• – Constraints on each data item.
• – Data items accessible by a user and the
• type of access.

System Catalog
It is used by modules such as:
• – Authorization Control.
• – Integrity Checker.
• Types of System Catalog:
• Active
• Passive

Interfaces to a Data Dictionary
Database
Administrators
Application
Programmers
End Users
Data Dictionary
Compilers /
Precompilers
Application Programs /
Report Generators
Integrity
Constraint
Enforcer
Human Interfaces
Software and
DBMS Interfaces

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

Database models
• 1960
s
• 1970s
• 1990s
Traditional
files
Hierarchical
Network
• 1980s
Relational
Object oriented
Object-relational
• 2000s
Client Oriented
?

Summary
• Definition of Database
• Types of database
• Range of databases
• Possible databases
• Components of database environment

Assignment # 1
Write down the detail definitions, functioning
structure with diagrams and advantages and
limitations for different Flavours of Client/Server
System:
• Transaction server
• Application server
• Data Server
• Compute Server
• Communication Server
• Video Server

Software Design and Architecture. -2.ppt

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