Kskv kutch university DBMS unit 1 basic concepts, data,information,database, models , network , hierarchical model

DBMSPost Graduate Diploma in Computer Application (PGDCA
1
KSKV kutch University

2DBMS
Basic Concepts – Data , information, database and DBMS
Data
o. Data are raw facts. The word raw indicate that the facts
have not yet been processed to reveal meaning
Information
o. Information is the result of processing raw data to reveal
its meaning.
o A data is known as the row fact which is stored in
computers memory and used by the user as the output.
o Collection of data its called information.
Example-House no 21C-S-1,Sch No 78 Indore
o Meaningful form of Data

3DBMS
Database:
oA collection of inter related data its called database.
o A database is a shared , integrated computer structure
that store a collection of end-user data and metadata
o A database is a collection of related data and data is
known as facts that can be recorded and that have implicit
meaning
oA database can be of any size and complexity
oA database may be generated and maintained manually or
it may be computerized.
Logically related and similar data

4DBMS
What is DBMS
o. A Database Management System is a collection of
programs that manage the database structure and controls
access to the data stored in the database
o Its allows to
o create databases
o insert , update and delete data
o sort and query data
o create form and reports

5DBMS
Schema
o The description of a database is called database schema.
o A database schema is specified during database design and
is not expected to change frequently
Instance
oThe data in the database at a particular moment in time is
called database state.
oA database is generally used by many users where insertion
and deletion of data occurs frequently. Overall information
stored in a database at a particular moment is called the
instance of the database.

6DBMS
Role and Advantages of DBMS
 Improved Data Sharing
 Improved Data security
 Minimized data inconsistency
 Improved Data Access
 Improved decision making
 Increased end-user productivity .
 Reduce application development time

7DBMS
Superkey
o An attribute that uniquely identifies each row in a table.
o E.g. :- cust_name and cust_id.
Candidate key
o A minimal superkey. A superkey that does not contain a
subset of attributes that is itself a superkey. E.g. :- cust_id
Primary Key
o A candidate key selected to uniquely identify all other
attribute values in any given row. Cannot contain null entries
Unique Key
o A candidate key selected to uniquely identify all other
attribute values in any given row
o Can accept unique or null values.

8DBMS
Foreign key
o An attribute in one table whose values must either match
the primary key in another table or be null.
Field
o A character or group of characters that has a specific
meaning. A filed is used to define and store data.
Record
o A logically connected set of one or more fields that
describes a person, place, or thing
File
o A collection of related record.

9DBMS
Database Applications
 Railway Reservation
 Library Management System
 Banking
 Schools and colleges
 Social media sites
 Telecommunication
 Finance
 Online shopping

1
0DBMS
What is data abstraction? Describe the levels briefly.
Data Abstraction Levels (i.e 2)

DBMS
1
1
Physical Level:
Conceptual Level:
View Level:
End-user View
(
(
Highest level.
Describes part of the
database for a particular
group of users.
Can be many different
views of a database.
E.g. tellers in a bank
get a view of customer
accounts, but not of
payroll data.
How the data are
stored.
E.g. index, B-tree,
hashing.
Lowest level of
abstraction.
Complex low-level
structures described in
detail.
Next highest level of
abstraction.
Describes what data
are stored.
Describes the
relationships among
data.
Database
administrator level.
 This level represents
only a part of the entire
database

1
2DBMS
Data Abstraction Levels

DBMS
Data Models and Types of Data Models
1
3
Data Model
A database model shows the logical structure
of a database, including the relationships and
constraints that determine how data can be stored
and accessed
Definition - What does Database Model mean?
A database model refers to the logical structure,
representation or layout of a database and how the data
will be stored, managed and processed within it. It helps
in designing a database and serves as blueprint for
application developers and database administrators in
creating a database
A Database model defines the logical design of
data. The model also describe the relationships between
different parts of the data.

DBMS
1
4
• in the hierarchical model, data is organized as an inverted tree,
Each entity has only one parent but can have several children. At
the top of the hierarchy , there is one entity, which is called the root
• The hierarchical data model organizes data in a tree structure
Hierarchical Model
PROFESSORS
PROFESSORS
No Name
ID Name CourseNo Name Unit
ID Name
DEPARTMENT
COURSES STUDENTS
ID Name

DBMS
1
5
Hierarchical Model
 The hierarchical model was the first database model developed to
overcome the limitations of the traditional file system
 Deletion of parent results in deletion of child records
 The hierarchical models was developed in the 1960 to manage
large amount of data for complex manufacturing projects such as
the Apollo rocket that landed on the moon in 1969.
 Its basic logical structure is represented by an upside-down tree
 The hierarchical structure contains levels or segments.
 The hierarchical model depicts a set of one-tomany relational ship
between a parents and its children segments
 tree like structure
 one parent may have multiple child but
 the child will have only parent

DBMS
1
6
Hierarchical Model
 The hierarchical model was the first database model developed to
overcome the limitations of the traditional file system
 Deletion of parent results in deletion of child records
 The hierarchical models was developed in the 1960 to manage
large amount of data for complex manufacturing projects such as
the Apollo rocket that landed on the moon in 1969.
 Its basic logical structure is represented by an upside-down tree
 The hierarchical structure contains levels or segments.
 The hierarchical model depicts a set of one-tomany relational ship
between a parents and its children segments
 tree like structure
 one parent may have multiple child but
 the child will have only parent

1
7DBMS
Disadvantages of hierarchical model
 complex implementation
 difficult to manage
 lack of structure independence
 complex application programing
 limitation in implementation
 Data depended on parent or root element

1
8
• In the network model, the entities are organized in a graph, in which
some entities can be accessed through several paths
• this model was developed to overcome the problems of hierarchical
model
Network model
DBMS
Network model
No Name ID Name Course
No Name Unit ID Name
DEPARTMENT
COURSES
STUDENTS
PROFESSORS

DBMS
1
9
Network model
 Graph structure
 Many-to-many relationships between linked records,
 Some data might have multiple parents
 Allow more connation between nodes
 ex. A employee work for two department is not possible in
hierarchical mode, but here it is possible
 The network model is a database model conveyed as a flexible
way of representing objects and their relationships

2
0DBMS
Advantages of network model
 Simple design
 Ability to handle many relationship
 Easy to access
 Data integrity ( current data, specify , fixed )
 Data independence
-Application programmers work independently of the data
-Any change made to the data do not affect application
programme

2
1
• In relational model, the data and relationships are represented by
collection of inter-related tables. Each table is a group of column and
rows, where column represents attribute of an entity and rows
represents records.
Relational model in DBMS
DBMS
Relational model

2
2
DBMS
Relational model
Attribute
Title Year Length
Star Wars 1977 124
Might Ducks 1991 104
Wayne’s World 1992 95
Table = relation.
Column headers = attributes
Tuple
Title Year Length
Star Wars 1977 124
Might
Ducks
1991 104
Wayne’s
World
1992 95
Table = relation.
Rows = tuple
• A relational database is a collection of one or more relations
where each relation is a table with rows and columns

2
3
DBMS
Relational model
 First proposed by Dr. E.F Codd of IBM Research in 1970
 Implemented through Relational DBMS (RDBMS)
 Represent database as a collection of relation
 Informally, each relation look like a table of values
 Represent database as a collections of relations
 Relation database matches data by using common
characteristics found within the data set
 The resulting groups of data are organized and are much easier
for people to understand.

2
4
• An entity relationship model, also called an entity-relationship (ER)
diagram, is a graphical representation of entities and their relationships
to each other, typically used in computing in regard to the organization
of data within databases or information systems. An entity is a piece of
data-an object or concept about which data is stored.
Entity Relationship Model
DBMS
ER model
title
year
length
name address
name
address
Studios
Star
MoviesOwns
Stars-in
filmType

2
5
ER Model is based on
DBMS • Entities and their attributes.
• Relationships among entities
Person
name
Is-insured
Entity Type
Attribute
Relationship
Type
 Entity – An object that exists or abstraction of similar things,
e.g. cars, students or people
Or – Distinguishable “thing” in the real world
 Attributes – common properties of the entities in a entity sets
e.g. students and people have names and addresses
Or – Each entity has certain characteristics known as attributes.
 Relationship – specify the relations among entities from two or more
entity sets

2
6
ER Model Diagram
DBMS
customer has
cust-street
cust-id
cust-name
cust-city
account
balance
number
access-date

2
7
ER Model Diagram , (Mapping)
DBMS
Many-to-Many1-to-1 1-to Many Many-to-1
 One to One(1:1) Relationship: and EMPLOYEE mangers one STORE;
each STORE is managed by one EMPLOYEE
 One to many (1:M) relationship: A PAINTER can paint many PAINTINGs;
each Painting is painted by one PAINTER
 Many to Many(M:N) Relationship: and EMPLOYEE can learn many SKILLs;
each SKILL can be learned by many EMPLYEEs.

2
8
Object Oriented Model
DBMS
Object Oriented model
• Data Stored in the form of objects, the structure which are called
“Classes” that display data within it.
• Defines database as a collection of objects that contains both data
members values and operations that are allowed on the data.
• Inter-relationship and constraints are implemented through objects and
links.
• The DBMS developed using this mode is called OODBMS
• Combine the capabilities of object oriented programming language
• Evolved to handle more complex applications such as database for
scientific experiments, geographic information system, CAD (computer
Aided Design)

2
9DBMS
Object Oriented model
Object Oriented Model
• In a below diagram customer and account are considered as a object

3
0DBMS
DDL, DML , DCL
DDL - Data Definition Language
o. Used by DB designers to define schema
DML - Data Manipulation Language
o. For accessing and manipulation the data
o. DDL compile converts DDL statements and generate a set
of tables which are stored in.
o. e.g - SQL, ORCALE
o. DML also known as query language
o. Procedural :- user specifies what data is required and how
to get those data.
o. Data dictionary contains metadata

3
1DBMS
DDL
 create, alter, drop, truncate, rename ,commit
DCL
 grant , revoke
DML
 insert, update , delete

KSKV kutch University
PGDCA (Post Graduate Diploma in Computer Application
To be Continue…..Unit 2

Kskv kutch university DBMS unit 1 basic concepts, data,information,database, models , network , hierarchical model

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Kskv kutch university DBMS unit 1 basic concepts, data,information,database, models , network , hierarchical model