M1G505190 Introduction to Database Development 1. Databases and Database Design.
Database 1 Introduction
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Transcript of Database 1 Introduction
February 23 , 2002 A. K. Ramani 1
WORKSHOP ON
DESIGN OF INFORMATION SYSTEMS FOR BUSINESS ORGANIZATIONS
by
A. K. RAMANI
DIRECTOR, IIPS, DAVV, INDORE
WELCOMEWELCOME
February 23 , 2002 A. K. Ramani 2
$ 10 Billion Industry
Shift of focus in research from Computation towards Information Management
Broadening application areas, like weather, genetic, entertainment, CAE, data warehousing, data mining, and decision making.
Advances in areas, like visualization, robotics, optical storage, high speed communications
MOTIVATIONMOTIVATION
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Motivation
Limited understanding of DB principles and techniques for advanced information management.Next generation DBs will need MM support, complex objects, real-time, rule processing…Co-operation in Scientific, engineering, commercial problems will need large scale heterogeneous distributed DBsRequirements: Efficiency, Resilience, Access control, Persistence
February 23 , 2002 A. K. Ramani 4
DBMSs to organize, create, and maintain collections of information.
Challenge is to apply DB technology in new and important areas in scientific databases, design databases, business, and utility databases and many more.
CHALLENGE OF DB TECH.CHALLENGE OF DB TECH.
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An Instant Virtual Enterprise (IVE) is a group of companies, that do not routinely function as a unit, come together to respond to a proposal of CIM. The task involves CAD, production, QA, Product planning, resource management etc.
In such an environment it is necessary for IVE companies to exchange and cooperatively manage the large amount of data.
SCENARIOSCENARIO
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A personnel information system provides information tailored to an individual, and delivered via a GPS of laptop, and access internet from any where any time, from waking up to bed time. Weather report, day special events, appointments, diet, best route, news headlines, sporting events, best investments, list of tasks, start of sale, best air ticket, best return route, preview of next day, by querying remote DBs.
SCENARIOSCENARIO
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The aim of this workshop is to help you developing an understanding of database development techniques in information management applications, and become an expert database developer.
AIMAIM
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OBJECTIVESOBJECTIVES
To familiarize with the concept of database development.To present the various steps in the approach to database development.To see an example of a DBMS oriented approach.
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EVOLUTION OF DATABASE TECHNOLOGIESEVOLUTION OF DATABASE TECHNOLOGIES
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Sequential Records
Index for random Access
Open, Close, Read, Write, Delete
Redundancy, inconsistency, poor data sharing,low productivity etc.
FILE SYSTEM FILE SYSTEM
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A conventional File Processing System
FILE SYSTEM FILE SYSTEM
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_ In file processing,each dept has own IS– For new system, new programs are needed
Disadvantages– Program data dependence - All program to be changed for
any change in file designs ( Record Formats)
– Duplication – Data inconsistency
– Poor Data Sharing – Incompatible files.
– Lengthy Development Times
Every new application start from scratch low productivityHigh maintenance cost 80% cost
FILE SYSTEM FILE SYSTEM
February 23 , 2002 A. K. Ramani 13
Hierarchical & Network Systems– Complex record structures
– Difficult to change application programs
Program
Class
STDDORM
STAFF
Course
Faculty
Employee
DATABASE MODELS DATABASE MODELS
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RELATIONAL MODELRELATIONAL MODEL
Relational DB Systems
– Data in Tables form
– Simple SQL
– Example DB2,ORACLE,INGRESS
– Difficult to handle Complex data & Relation ships
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Object Oriented Modeling
Program
Class
STDDORM
STAFF
Course
Faculty
Employee
DATABASE MODELS DATABASE MODELS
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Student
Name,DOB,GPA
take Course
------
------
Faculty
Name,Rank Salary
Advice
Research
------
Course
Title,Credit
Pre requisite
Class
Time
Assign Lab
is advised by
TakeTeach
OBJECT MODELOBJECT MODEL
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Object oriented model
For complex Relationships
UML (Unified Modeling Language)
Easy to maintain & Change
Improved Productivity
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Aim Introduce different concepts of DBMS, in context of Information System development.
Objectives– Define database & related terms
– Understand DBMS components , role & DBMS architecture
– Limitations of Conventional File System
– Introduce DB approach , ER concept , Categories of DB applications & issue
– Advantage of DB approach
– Evolution of DBMS
INTRODUCTION TO DBMSINTRODUCTION TO DBMS
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Database is a data bank, where data can be stored manipulated and retrieved in a speedy manner, efficiently and error free.A database is a model of structures of realityThe use of a database reflect processes of realityA database system is a software system which supports the definition and use of a databaseDDL: Data Definition LanguageDML: Data Manipulation Language
WHAT IS A DATABASEWHAT IS A DATABASE
REALITY
• structures
• processes
DATABASE SYSTEM
DATABASE
DML
DDL
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Database is a representation of a part of real world in terms of computable objects.
E = {Object,Attributes,Data}, where E is an Entity.
D = {E1,E2,………En}, where D is database
– How to implant changes in database
By using a set of software modules.– DBMS = Database + S/W modules
S/W DB
Applications
Tools
Applications DB S/W Data
Data Base
Database
WHAT IS A DATABASEWHAT IS A DATABASE
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Data– is a known (valued) fact.– is a value to an attribute– can be recorded on computer mediaExample : This house has four rooms.Database = Object + data + attributes– Data can comprise of facts,which may include numeric,text,
images, sound & multimedia.– Database is an organized collection of logically related data
where data can be stored easily, manipulated,retrieved.– Data becomes information when processed.– Meta Data are data that describe the properties of data,
include data definitions, data sizes, rules, constraints etc.
February 23 , 2002 A. K. Ramani 22
Data Collection– Data - Stores facts– Information – Extracted & derived data for a specific purpose
DBMS Software– Efficiently and reliably manages data storage, retrieval, data update
(Insert, Modify, Delete)
Automated Tools– For design,query and application development
Database Users– End Users– Data Analysts & Application Programmer– DB designers– DBA
DATABASE COMPONENTSDATABASE COMPONENTS
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Field – It is a set of bytes to represent some values,lowest
level of database ( or logical structure)
Record– Group of logically related fields,records accessed
via S/W
File– A group of identical records,accessible via system
software
Database– A set of related files , accessed via system software.
DEFINITIONDEFINITION
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Insert Picture of slide 5
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Use a DBMS when this is important
persistent storage of data
centralized control of data
control of redundancy
control of consistency and integrity
multiple user support
sharing of data
data documentation
data independence
control of access and security
backup and recovery
WHEN TO USE DBMSWHEN TO USE DBMS
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Do not use a DBMS when
the initial investment in hardware, software, and training is too high
the generality a DBMS provides is not needed
the overhead for security, concurrency control, and recovery is too high
data and applications are simple and stable
real-time requirements cannot be met by it
multiple user access is not needed
WHEN NOT TO USE DBMSWHEN NOT TO USE DBMS
Applications programs / Queries
Software for queries / Programs
Software to access data base
Meta Data DB
TransactionsDatabase System
Software Modules
DBMS ARCHITECTUREDBMS ARCHITECTURE
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The purpose of database design is to create a database which
is a model of structures of realitysupports queries and updates modeling processes of realityruns efficiently
DB approach is total integration and sharing of data throughout the organization
DATABASE DESIGNDATABASE DESIGN
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Goal : Business Strategies supported upon IT 3 Steps1. Identify strategic planning factors
• Goals : Growth Rate……..• Success Factors : Quality,On-time…..• Problem Areas : Competition….
Set priorities of needs of IS & DB 2. Identify Corporate Planning objects
1. Organizational Units – Various depts2. Locations – business places3. Business Functions – business processes like product development
4. Entity Types : Categories of data about people,places & things managed by company 5. Information System : Application S/W & supporting procedures.
IS PLANNINGIS PLANNING
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Develop list of Entities that support the business activities– An entity is an object/concept that is important to business, e,g,
CUSTOMER,PRODUCT,EMPLOYEE,ORDER etc
– Identification & definition of Entities.
Develop Enterprise Data Model to show association among entities. Also called as E-R models.
Customer
Order
Product
Order Line
Places
is Placed by
has
is for
Contains is containedin
IS PLANNINGIS PLANNING
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Entities– Customer : People / Companies / potential customer– Order : Purchase of 1 or more items– Product : Items produced for selling– Order Line : Details of each product (quantity price ) sold on
a particular customer
Apply Business Rules For Relation ShipsEach Customer places >= 1 OrderEach order is placed by one CustomerEach order contains >=1 L (ask slide 10)Each L is contained in One Customer Order (O)Each product has >=1 LEach order line is for one product
IS PLANNINGIS PLANNING
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ER Model– Tells how organization functions and constraints
– Emphasizes on data & process by considering data, relationships & business rules.
Relational Databases– Data is viewed in form of tables
– Tables are based upon entities of ER model and contains attributes of an entity and its instances (value)
– Few attributes are common among tables e.g. ID nos., Employee number
Historical and summarized information (ask it) data base is called Data Ware House ( D-Mgt ask it) to assist DSS.
Data base application program can perform actions like Create, Read, Update, Delete etc.
IS PLANNINGIS PLANNING
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Area of Application
Perspective
Work-Processes
Guidelines for Work-Processes in the development of the application
DATABASE DEVELOPMENTDATABASE DEVELOPMENT
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Development of medium to large size data intensive applicationsData intensive: – lots of data– little processing– insertions, deletions, updates,– queries
What is medium to large? Small is:– well-defined project– short development time– no long-term maintenance– few people; little turnover– no critical resources– small risk of failure– small cost of failure
Why only medium to large?– the methodology is an insurance policy– cost of using methodology is high
AREA OF APPLICATIONAREA OF APPLICATION
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Business process is well-designedDocuments are knownTasks are knownSystem boundary is knownOne database schema unifying all views can be designed– difficult: interests, goals, power, politics– problems with the methodology?– problems with the organization?– or-gan-i-za-tion: “an entity created to pursue a shared
set of goals”
PERSPECTIVEPERSPECTIVE
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Business process (re-)designAnalysisSpecificationDesignImplementationTestingOperationMaintenance
Managem
ent
WORK PROCESSESWORK PROCESSES
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Purpose: what we do?Input: what we start with?Output: what we end with?Tool: what we use?Technique: how we use it?Organization: who does what?
GUIDELINES FOR WORK-PROCESSESEGUIDELINES FOR WORK-PROCESSESE
February 23 , 2002 A. K. Ramani 38
waterfall model; this is not prototypingiteration necessarywork vs. time vs. peopleestimating resources is very difficult
work-process
time
analysis specification design implementation test
TIME AND MANAGEMENTTIME AND MANAGEMENT
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Type User Architecture Size1. PC 1 Desktop Megabytes
2. WorkGroup 5-25 Client/Server (2 Tier) M-G bytes
3. Department 25-100 Client/Server (3 Tier) G bytes
4. Enterprise > 100 Client/server (Distributed) G-Terabytes
CATEGORIES OF DB APPLICATIONCATEGORIES OF DB APPLICATION
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Optimized Database Design
Integrity of Database
Performance
Security
Redundancy & Consistency
Distributed Database Designs
DATABASE ISSUEDATABASE ISSUE
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Program-Data Independence– Metadata & programmes are independent
Minimal Redundancy– Single logical structure
Data Consistency– Each value stored on one place
Data Sharing– To form report from more than 1 table
Increased Productivity in Development– Saves cost/time
Enforcement of Standards– Feasible
Improved Data Quality– Enforce constraints– Data Management approach
Simplicity in Data Access– Select * from product where Product_name =“Computer” ;
It is a SQL commandEasy Maintenance
– Y2k Problem
ADVANTAGES OF DB APPROACHADVANTAGES OF DB APPROACH
February 23 , 2002 A. K. Ramani 42
Expensive New H/W , Operating Cost
Complex Development/Implement
Recovery more difficult
Vulnerability to failure
Organizational Conflicts strong top management support must.
DISADVANTAGESDISADVANTAGES
February 23 , 2002 A. K. Ramani 43
Future Trends– Object – Relational Databases
– Distributed Databases• Distributed to multiple locations,transparent
– Content Addressable
– Interface other technologies like AI, TV, Natural Language Interface
Summary– Database & related terms
– DB approach,Advantages
– Categories,Evolution
– Future Trends
FUTURE TREND AND SUMMARYFUTURE TREND AND SUMMARY