data base management system (DBMS)

NOIDA BRANCH OF CIRC
OF ICAI
VARISH BAJAJ
DATA BASE MANAGEMENT
SYSTEM
Mr. OM PRAKASH
(ITT FACULTY)

Introduction to DBMS
(Database Management Systems)
Application
program
End-user
DBMS

Database Overview
Database
What, Why, How
Evolution of Database
File System
Data Models
Hierarchical
Network
Relational
Entity-Relationship
Object-Oriented
Web Database

Database: What
 Database
 is collection of related data and its metadata organized in a structured
format
 for optimized information management
 Database Management System (DBMS)
 is a software that enables easy creation, access, and modification of
databases
 for efficient and effective database management
 Database System
 is an integrated system of hardware, software, people, procedures, and
data
 that define and regulate the collection, storage, management, and use
of data within a database environment

Database Management System
Database Systems: Design, Implementation, & Management: Rob & Coronel
- manages interaction between end users and database

Database: Why
 Purpose of Database
Optimizes data management
Transforms data into information
 Importance of Database Design
Defines the database’s expected use
Avoid data redundancy & ensure data integrity
Poorly designed database generates errors
 Functions of DBMS/Database System
Stores data and related data entry forms, report
definitions, etc.
Hides the complexities of relational database model
from the user
Enforces data integrity
Implements data security management

Database: How
 Planning & Analysis
Assess
Goal of the organization
Database environment
 existing hardware, software, raw data, data processing procedures
Identify
Database needs
 what database can do to further the goal of the organization
User needs and characteristics
 who the users are, what they want to do, how they envision doing it
Database system requirements
 what the database system should do to satisfy the database and user
needs
 Design
From conceptual design to a detailed system specification
 Implementation
Create the database
 Maintenance
Troubleshoot, update, streamline the database

Business Rules
What
 Brief, precise, and unambiguous descriptions of operations in an
organization
Why
 Enhance understanding & facilitate communication
 Promote creation of an accurate data model
How (sources)
 Interviews
 Written documentation
 Observation

Database: Data Models
 Importance
 Abstraction of complex real-word data structures in relative simple
(graphical) representations
 Facilitate interaction among the designer, the applications programmer,
and the end user
 Basic Building Blocks
 Entity
 thing about which data are to be collected and stored
 Attribute
 a characteristic of an entity
 Relationship
 describes an association among entities
 Constraint
 restrictions placed on the data

Hierarchical Database
 Background
 Developed to manage large amount of data for complex manufacturing
projects
 e.g., Information Management System (IMS)
 IBM-Rockwell joint venture
 clustered related data together
 hierarchically associated data clusters using pointers
 Hierarchical Database Model
 Assumes data relationships are hierarchical
 One-to-Many (1:M) relationships
 Each parent can have many children
 Each child has only one parent
 Logically represented by an upside down tree

Hierarchical Database: Example
Database Systems: Design,
Implementation, & Management: Rob &
Coronel

Hierarchical Database: Pros
& Cons
 Advantages
 Conceptual simplicity
 groups of data could be related to each other
 related data could be viewed together
 Centralization of data
 reduced redundancy and promoted consistency
 Disadvantages
 Limited representation of data relationships
 did not allow Many-to-Many (M:N) relations
 Complex implementation
 required in-depth knowledge of physical data storage
 Structural Dependence
 data access requires physical storage path
 Lack of Standards
 limited portability

Database Administrator
 Coordinates all the activities of the database system;
the database administrator has a good understanding
of the enterprise’s information resources and needs:
 Database administrator’s duties include:
 Schema definition
 Storage structure and access method definition
 Schema and physical organization modification
 Granting user authority to access the database
 Specifying integrity constraints
 Acting as liaison with users
 Monitoring performance and responding to changes in
requirements

Structure of a DBMS
• A typical DBMS has a
layered architecture.
• The figure does not
show the concurrency
control and recovery
components.
• Each database system
has its own variations.
Query Optimization
and Execution
Relational Operators
Files and Access Methods
Buffer Management
Disk Space Management
DB
These layers
must consider
concurrency
control and
recovery

Overall System Structure
indices Statistical data
Data files Data dictionary
disk storage

Use of a Database Management System in
Design and Application
Design
Analysis
Design
Verification
Evaluation Synthesis Release
Manufacturing
Planning
Production
Control
Project
Management
APPLICATION
DBMS
Database Management
System
Graphic Interface Language InterfaceINTERFACE
Preliminary-
design
Analysis
Models
Detailed
Design
Design
Release
Control
Fabrication
Assembly
Info
Test /
Inspection
Database Manufacturing

Advantages of a DBMS
 Data independence
 Efficient data access
 Data integrity & security
 Data administration
 Concurrent access, crash recovery
 Reduced application development time
 So why not use them always?
 Expensive/complicated to set up & maintain
 This cost & complexity must be offset by need
 General-purpose, not suited for special-purpose tasks (e.g. text
search!)

Levels of Abstraction
• Views describe how
users see the data.
• Conceptual schema
defines logical
structure
• Physical schema
describes the files and
indexes used.
• (sometimes called the
ANSI/SPARC model)
Physical Schema
Conceptual Schema
View 1 View 2 View 3
DB

Reports and Their Anatomy
• Columnar report vs. Tabular report
• Report header & footer
• Page header & footer
• Group header & footer
• Detail section
• Report Wizard

Report View
Report Header
Page Header
Detail Section

Report Design View
Report Header
Page Header
Detail Section
Page footer

Creating a Query
Select query
Query window views
- Datasheet view
- Design view
- SQL view

Creating a Query--Selection
Criteria
• AND condition
• OR condition
• Relational operators
• Between function
• NOT function
• Wild card

Creating a Select Query
Hands-On Exercise
• Open Database
• Add Students Table
• Create Query
• Specify Criteria
•Run the Query
•Modify Query
•Create a Report
•View the Report

Select Query Design View
table
criteria
Run button

Example: A Simple Query
Processing
Query in SQL：
SELECT CUSTOMER. NAME
FROM CUSTOMER, INVOICE
WHERE REGION = 'N.Y.' AND
AMOUNT > 10000 AND
CUTOMER.C#=INVOICE.C
Internal Form :
((S SP)
Operator :
SCAN C using region index, create C
SCAN I using amount index, create I
SORT C?and I?on C#
JOIN C?and I?on C#
EXTRACT name field
Calls to Access Method：
OPEN SCAN on C with region index
GET next tuple
.
.
.
Calls to file system：
GET10th to 25th bytes from
block #6 of file #5
Language Processor
Optimizer
Operator Processor
Access Method
File System
database
Language
Processor
Access
Method
e.g.B-tree; Index;
Hashing
DBMS

Primary Key
primary key fields
A primary key can consist of more than one field.

Foreign Key
foreign key field
primary key field
parent tableDirectors
Movies
child tablerelationship

The Key
• Super Key
• Candidate Key
• Primary Key
• Alternate Key
• Secondary Key
• Foreign Key

Super key
 A super key is a set of one or more attributes which taken
collectively.
 It allow us to identify uniquely an entity instance in the entity set like
program and course code.
 An entity type, its defining attributes and super key (underlined)

Primary key
• A candidate key chosen by the database
• designer to act as key is the primary key.
• candidate keys, in that case the database
• Designer has to designate one of them as a primary key,

One-To-Many Relationship
• In the one-to-many relationship a loan is associated with at
most one customer via borrower, a customer is associated with
several (including 0) loans via borrower

Many-To-One Relationships
• In a many-to-one relationship a loan is associated with several
(including 0) customers via borrower, a customer is associated
with at most one loan via borrower

Many-To-Many Relationship
• A customer is associated with several (possibly 0) loans via
borrower
• A loan is associated with several (possibly 0) customers via
borrower

data base management system (DBMS)

data base management system (DBMS)

Recommended

More Related Content

What's hot (20)

Similar to data base management system (DBMS) (20)

Recently uploaded (20)

data base management system (DBMS)