database management system
Content
DATABASE
MANAGEMENT
SYSTEM
Prepared byMehul Agrawal (CRO - 0533416)
ROLL NO.-12
Instructor: Anil Kumar
Sharma
I.T.T Batch no. 63
ACKNOWLEDGEMENT
I would like to express my special
thanks of gratitude to my teacher
ANIL KUMAR SHARMA as well as ICAI
which gave me the golden
opportunity to do this wonderful
project on the topic DATABASE
MANAGEMENT SYSTEM which also
helped me in doing a lot of Research
and i came to know about so many
new things I am really thankful to
CONTENTS
WHAT IS DBMS?
ADVANTAGES OF DBMS
USERS OF DBMS
3- TIER ARCHITECTURE
DATABASE SCHEMA
DATA MODELS
DATABASE INSTANCE
DATA INDEPENDENCE
RELATIONAL DATA MODEL CONCEPTS
WHY USE A DBMS?
DISADVANTAGES OF DBMS
SUMMARY
What Is a DBMS?
A very large, integrated collection of data.
Models real-world enterprise.
Entities (e.g., students, courses)
Relationships (e.g., Madonna is taking
CS564)
A Database Management System (DBMS)
is a software package designed to store
and manage databases.
ADVANTAGES OF DBMS
A modern DBMS has the following characteristics −
Less redundancy − DBMS follows the rules of
normalization, which splits a relation when any of its
attributes is having redundancy in values.
Normalization is a mathematically rich and scientific
process that reduces data redundancy.
Consistency − Consistency is a state where every
relation in a database remains consistent. A DBMS can
provide greater consistency as compared to earlier
forms of data storing applications like file-processing
systems.
ACID Properties − DBMS follows the concepts
of Atomicity,Consistency, Isolation,
and Durability (normally shortened as ACID).
ACID properties help the database stay healthy
in multi-transactional environments and in case
of failure.
Multiuser and Concurrent Access − DBMS
supports multi-user environment and allows
them to access and manipulate data in parallel.
Though there are restrictions on transactions
when users attempt to handle the same data
item, but users are always unaware of them.
USERS
Administrators − Administrators maintain the
DBMS and are responsible for administrating the
database. They are responsible to look after its
usage and by whom it should be used. They
create access profiles for users and apply
limitations to maintain isolation and force security.
Administrators also look after DBMS resources like
system license, required tools, and other software
and hardware related maintenance.
Designers − Designers are the group of people who
actually work on the designing part of the database.
They keep a close watch on what data should be kept
and in what format. They identify and design the
whole set of entities, relations, constraints, and views.
End Users − End users are those who actually reap
the benefits of having a DBMS. End users can range
from simple viewers who pay attention to the logs or
market rates to sophisticated users such as business
analysts.
3-TIER ARCHITECTURE
A 3-tier architecture separates its tiers from
each other based on the complexity of the
users and how they use the data present in
the database. It is the most widely used
architecture to design a DBMS.
Database (Data) Tier − At this tier, the
database resides along with its query
processing languages.
Application (Middle) Tier − At this tier
reside the application server and the programs
that access the database.
User (Presentation) Tier − End-users
operate on this tier and they know nothing
about any existence of the database beyond
this layer.
DATABASE SCHEMA
A database schema is the skeleton structure that
represents the logical view of the entire database.
It defines how the data is organized and how the
relations among them are associated.
A database schema can be divided broadly into two
categories −
Physical Database Schema − This schema
pertains to the actual storage of data and its form
of storage like files, indices, etc. It defines how
the data will be stored in a secondary storage.
Logical Database Schema − This schema
defines all the logical constraints that need to
be applied on the data stored.
Example: University Database
Conceptual schema:
Students(sid: string, name: string, login: string,
age: integer, gpa:real)
Courses(cid: string, cname:string, credits:integer)
Enrolled(sid:string, cid:string, grade:string)
Physical schema:
Relations
stored as unordered files.
Index on first column of Students.
External Schema (View):
Course_info(cid:string,enrollment:integer)
DATA MODELS
Entity-Relationship Model
Entity-Relationship (ER) Model is based on the
notion of real-world entities and relationships
among them. While formulating real-world
scenario into the database model, the ER
Model creates entity set, relationship set,
general attributes and constraints.
Relational Model
The most popular data model in DBMS is the
Relational Model. It is more scientific a model
than others. This model is based on first-order
predicate logic and defines a table as an nary relation.
DATABASE INSTANCE
A database instance is a state of operational
database with data at any given time. It
contains a snapshot of the database.
Database instances tend to change with time.
A DBMS ensures that its every instance
(state) is in a valid state, by diligently
following all the validations, constraints, and
conditions that the database designers have
imposed.
DATA INDEPENDENCE
A database system normally contains a lot of
data in addition to users’ data. For example, it
stores data about data, known as metadata,
to locate and retrieve data easily. It is rather
difficult to modify or update a set of metadata
once it is stored in the database. But as a
DBMS expands, it needs to change over time
to satisfy the requirements of the users.
Logical data independence is a kind of mechanism, which
liberalizes itself from actual data stored on the disk.
Physical data independence is the power to change the physical
data without impacting the schema or logical data.
RELATIONAL DATA MODEL
CONCEPTS
Tables − In relational data model, relations are
saved in the format of Tables. This format stores the
relation among entities. A table has rows and
columns, where rows represents records and
columns represent the attributes.
Tuple − A single row of a table, which contains a
single record for that relation is called a tuple.
Relation instance − A finite set of tuples in the
relational database system represents relation
Relation schema − A relation schema describes
the relation name (table name), attributes, and
their names.
Relation key − Each row has one or more
attributes, known as relation key, which can
identify the row in the relation (table) uniquely.
Attribute domain − Every attribute has some predefined value scope, known as attribute domain.
Why Use a DBMS?
Data independence and efficient access.
Reduced application development time.
Data integrity and security.
Uniform data administration.
Concurrent access, recovery from crashes.
DISADVANTAGES OF
DBMS
Although there are many advantages of DBMS, the DBMS may also
have some minor disadvantages. These are:
Cost of Hardware and Software
A processor with high speed of data processing and memory of
large size is required to run the DBMS software. It means that you
have to up grade the hardware used for file-based system. Similarly,
DBMS software is also very costly,.
Cost of Data Conversion
When a computer file-based system is replaced with database
system, the data stored into data file must be converted to database
file. It is very difficult and costly method to convert data of data file
into database. You have to hire database system designers along
with application programmers.
Cost of Staff Training
Most database management system are often complex systems
so the training for users to use the DBMS is required. Training is
required at all levels, including programming, application
development, and database administration. The organization has
to be paid a lot of amount for the training of staff to run the
DBMS.
Appointing Technical Staff
The trained technical persons such as database administrator,
application programmers, data entry operations etc. are required
to handle the DBMS. You have to pay handsome salaries to these
persons. Therefore, the system cost increases.
Database Damage
In most of the organization, all data is integrated into a single
database. If database is damaged due to electric failure or
database is corrupted on the storage media, the your valuable
data may be lost forever.
THANK YOU
MANAGEMENT
SYSTEM
Prepared byMehul Agrawal (CRO - 0533416)
ROLL NO.-12
Instructor: Anil Kumar
Sharma
I.T.T Batch no. 63
ACKNOWLEDGEMENT
I would like to express my special
thanks of gratitude to my teacher
ANIL KUMAR SHARMA as well as ICAI
which gave me the golden
opportunity to do this wonderful
project on the topic DATABASE
MANAGEMENT SYSTEM which also
helped me in doing a lot of Research
and i came to know about so many
new things I am really thankful to
CONTENTS
WHAT IS DBMS?
ADVANTAGES OF DBMS
USERS OF DBMS
3- TIER ARCHITECTURE
DATABASE SCHEMA
DATA MODELS
DATABASE INSTANCE
DATA INDEPENDENCE
RELATIONAL DATA MODEL CONCEPTS
WHY USE A DBMS?
DISADVANTAGES OF DBMS
SUMMARY
What Is a DBMS?
A very large, integrated collection of data.
Models real-world enterprise.
Entities (e.g., students, courses)
Relationships (e.g., Madonna is taking
CS564)
A Database Management System (DBMS)
is a software package designed to store
and manage databases.
ADVANTAGES OF DBMS
A modern DBMS has the following characteristics −
Less redundancy − DBMS follows the rules of
normalization, which splits a relation when any of its
attributes is having redundancy in values.
Normalization is a mathematically rich and scientific
process that reduces data redundancy.
Consistency − Consistency is a state where every
relation in a database remains consistent. A DBMS can
provide greater consistency as compared to earlier
forms of data storing applications like file-processing
systems.
ACID Properties − DBMS follows the concepts
of Atomicity,Consistency, Isolation,
and Durability (normally shortened as ACID).
ACID properties help the database stay healthy
in multi-transactional environments and in case
of failure.
Multiuser and Concurrent Access − DBMS
supports multi-user environment and allows
them to access and manipulate data in parallel.
Though there are restrictions on transactions
when users attempt to handle the same data
item, but users are always unaware of them.
USERS
Administrators − Administrators maintain the
DBMS and are responsible for administrating the
database. They are responsible to look after its
usage and by whom it should be used. They
create access profiles for users and apply
limitations to maintain isolation and force security.
Administrators also look after DBMS resources like
system license, required tools, and other software
and hardware related maintenance.
Designers − Designers are the group of people who
actually work on the designing part of the database.
They keep a close watch on what data should be kept
and in what format. They identify and design the
whole set of entities, relations, constraints, and views.
End Users − End users are those who actually reap
the benefits of having a DBMS. End users can range
from simple viewers who pay attention to the logs or
market rates to sophisticated users such as business
analysts.
3-TIER ARCHITECTURE
A 3-tier architecture separates its tiers from
each other based on the complexity of the
users and how they use the data present in
the database. It is the most widely used
architecture to design a DBMS.
Database (Data) Tier − At this tier, the
database resides along with its query
processing languages.
Application (Middle) Tier − At this tier
reside the application server and the programs
that access the database.
User (Presentation) Tier − End-users
operate on this tier and they know nothing
about any existence of the database beyond
this layer.
DATABASE SCHEMA
A database schema is the skeleton structure that
represents the logical view of the entire database.
It defines how the data is organized and how the
relations among them are associated.
A database schema can be divided broadly into two
categories −
Physical Database Schema − This schema
pertains to the actual storage of data and its form
of storage like files, indices, etc. It defines how
the data will be stored in a secondary storage.
Logical Database Schema − This schema
defines all the logical constraints that need to
be applied on the data stored.
Example: University Database
Conceptual schema:
Students(sid: string, name: string, login: string,
age: integer, gpa:real)
Courses(cid: string, cname:string, credits:integer)
Enrolled(sid:string, cid:string, grade:string)
Physical schema:
Relations
stored as unordered files.
Index on first column of Students.
External Schema (View):
Course_info(cid:string,enrollment:integer)
DATA MODELS
Entity-Relationship Model
Entity-Relationship (ER) Model is based on the
notion of real-world entities and relationships
among them. While formulating real-world
scenario into the database model, the ER
Model creates entity set, relationship set,
general attributes and constraints.
Relational Model
The most popular data model in DBMS is the
Relational Model. It is more scientific a model
than others. This model is based on first-order
predicate logic and defines a table as an nary relation.
DATABASE INSTANCE
A database instance is a state of operational
database with data at any given time. It
contains a snapshot of the database.
Database instances tend to change with time.
A DBMS ensures that its every instance
(state) is in a valid state, by diligently
following all the validations, constraints, and
conditions that the database designers have
imposed.
DATA INDEPENDENCE
A database system normally contains a lot of
data in addition to users’ data. For example, it
stores data about data, known as metadata,
to locate and retrieve data easily. It is rather
difficult to modify or update a set of metadata
once it is stored in the database. But as a
DBMS expands, it needs to change over time
to satisfy the requirements of the users.
Logical data independence is a kind of mechanism, which
liberalizes itself from actual data stored on the disk.
Physical data independence is the power to change the physical
data without impacting the schema or logical data.
RELATIONAL DATA MODEL
CONCEPTS
Tables − In relational data model, relations are
saved in the format of Tables. This format stores the
relation among entities. A table has rows and
columns, where rows represents records and
columns represent the attributes.
Tuple − A single row of a table, which contains a
single record for that relation is called a tuple.
Relation instance − A finite set of tuples in the
relational database system represents relation
Relation schema − A relation schema describes
the relation name (table name), attributes, and
their names.
Relation key − Each row has one or more
attributes, known as relation key, which can
identify the row in the relation (table) uniquely.
Attribute domain − Every attribute has some predefined value scope, known as attribute domain.
Why Use a DBMS?
Data independence and efficient access.
Reduced application development time.
Data integrity and security.
Uniform data administration.
Concurrent access, recovery from crashes.
DISADVANTAGES OF
DBMS
Although there are many advantages of DBMS, the DBMS may also
have some minor disadvantages. These are:
Cost of Hardware and Software
A processor with high speed of data processing and memory of
large size is required to run the DBMS software. It means that you
have to up grade the hardware used for file-based system. Similarly,
DBMS software is also very costly,.
Cost of Data Conversion
When a computer file-based system is replaced with database
system, the data stored into data file must be converted to database
file. It is very difficult and costly method to convert data of data file
into database. You have to hire database system designers along
with application programmers.
Cost of Staff Training
Most database management system are often complex systems
so the training for users to use the DBMS is required. Training is
required at all levels, including programming, application
development, and database administration. The organization has
to be paid a lot of amount for the training of staff to run the
DBMS.
Appointing Technical Staff
The trained technical persons such as database administrator,
application programmers, data entry operations etc. are required
to handle the DBMS. You have to pay handsome salaries to these
persons. Therefore, the system cost increases.
Database Damage
In most of the organization, all data is integrated into a single
database. If database is damaged due to electric failure or
database is corrupted on the storage media, the your valuable
data may be lost forever.
THANK YOU
