DBMS_Chapter1_Introduction_to_database.pptx

Module 1
INTRODUCTION TO DATABASE

What is Data?
It is a fact that can be recorded and has a implicit meaning
Eg: Student entity

What is database
It is a collection of interrelated data which is stored in the tabular format
Eg: Student database
St_rollno St_name St_DOB St_Add St_phno St_stream
121 ABS 19 JUL 2000 SSS 8574123698 QQQ
123 KJL 20 OCT 2000 AAA 8574111023 ZZZ
125 OUY 14 JAN 2001 VVV 7469812036 FFF

What is DBMS
A Database Management System (DBMS) is a software system designed to store, manage,
and interact with databases. It provides a structured and efficient way to create, access,
update, and organize data in a database, allowing users and applications to perform various
operations on the data.
Key functions of a DBMS
1. Data Storage
2. Data Retrieval
3. Data Manipulation
4. Data Security
5. Data Integrity
6. Backup and Recovery
7. Concurrency Control

Comparison between traditional file and DBMS
File System DBMS
It is the method of storing the data in the
storage medium within the computer
It is a s/w which is used for managing
database
Query Processing is not applicable Query Processing is applicable
Redundancy of data will occur This S/W does not produce redundant data
Data inconsistency will occur Data’s are consistent
It consumes only less amount of memory It is expensive as it consumes large amount
of memory
Example: CPP Example: oracle, mysql

Characteristics of database approach
● There are number of characteristics that distinguish the database approach from the much
older approach of programming with files. In traditional file processing, each user defines
and implements the files needed for a specific software application as part of
programming the application.
● For example, one user, the grade reporting office, may keep files on students and their
grades. Programs to print a student’s transcript and to enter new grades are implemented
as part of the application.
● A second user, the accounting office, may keep track of students’ fees and their payments.

● Although both users are interested in data about students, each user maintains separate
files— and programs to manipulate these files—because each requires some data not
available from the other user’s files.
● This redundancy in defining and storing data results in wasted storage space and in
redundant efforts to maintain common up-to-date data.In the database approach, a single
repository maintains data that is defined once and then accessed by various users.
● In file systems, each application is free to name data elements independently. In contrast,
in a database, the names or labels of data are defined once, and used repeatedly by
queries, transactions, and applications.

Characteristics of database approach includes:
Self describing nature of the Database system:
● A fundamental characteristics of database approach is that the database system contains
not only the database itself but also a complete definition or description of the database
structure and constraints. This definition is stored in the DBMS catalog, which contains
information such as the structure of each file, the type and storage format of each data
item, and various constraints on the data. The information stored in the catalog is called
meta-data, and it describes the structure of the primary database.

● The catalog is used by the DBMS software and also by database users who need
information about the database structure. A general-purpose DBMS software package is
not written for a specific database application. Therefore, it must refer to the catalog to
know the structure of the files in a specific database, such as the type and format of data it
will access. The DBMS software must work equally well with any number of database
applications—for example, a university database, a banking database, or a company
database—as long as the database definition is stored in the catalog.
● Consider the example of database catalog. These definitions are specified by the database
designer prior to creating the actual database and are stored in the catalog. Whenever a
request is made to access, say, the Name of a STUDENT record, the DBMS software
refers to the catalog to determine the structure of the STUDENT file and the position and
size of the Name data item within a STUDENT record.

Insulation between programs and data, data Abstraction:
In DBMS, the structure of the database is stored in the database catalog. If a new attribute is
added, the application does not need major code modifications because DBMS separates data
storage from application logic. Instead, only the DBMS catalog needs to be updated, ensuring
insulation between programs and data.
Data Abstraction in DBMS is the process of hiding complex details of how data is stored and
maintained, allowing users to interact with data at a higher level without worrying about
internal implementation.

Support of multiple views of data:
In a Database Management System (DBMS), support of multiple views of data refers to
the ability to present different perspectives or subsets of the database to different users or
applications, depending on their specific needs or roles. Each view is essentially a virtual
table derived from the underlying database schema, and it can contain a subset of the
data, aggregate data, or even present the data in a format that simplifies its use for a
particular purpose.
For example:
● A student view might show only a student's personal information and grades,
without exposing sensitive data like financial details.
● An administrator view might include all the data in the database, with full access to
all records and tables.

Sharing of Data & Multi User Transaction Processing:
● A multi user DBMS, as its name implies, must allow multiple users to access the
database at the same time. This is essential if data for multiple applications is to be
integrated and maintained in a single database. The DBMS must include concurrency
control software to ensure that several users trying to update the same data do so in a
controlled manner so that the result of the updates is correct.
● For example, when several reservation agents try to assign a seat on an airline flight,
the DBMS should ensure that each seat can be accessed by only one agent at a time for
assignment to a passenger. These types of applications are generally called online
transaction processing (OLTP) applications. A fundamental role of multi user DBMS
software is to ensure that concurrent transactions operate correctly and efficiently.

● The DBMS must enforce several transaction properties. The isolation
property ensures that each transaction appears to execute in isolation
from other transactions, even though hundreds of transactions may be
executing concurrently. The atomicity property ensures that either all
the database operations in a transaction are executed or none are. The
preceding characteristics are important in distinguishing a DBMS
from traditional file-processing software.

Database users
A Database Management System (DBMS) has different types of users based on their roles,
permissions, and interaction with the database. These users ensure efficient data management,
security, and retrieval.
● Database Administrator (DBA)
The DBA is a person responsible for managing, maintaining, and securing a database system.
The DBA ensures the availability, performance, security, and integrity of the database while
also handling backup, recovery, and user access control.
Example: A DBA in a bank ensures customer data is secure, queries are optimized, and
backups are regularly taken to prevent data loss.

● Naive Users / parametric users
A Naïve User is a type of database user who interacts with the database without writing
queries or understanding the internal workings of the database. They typically use predefined
applications, forms, or interfaces to access data.
Example: A student accessing a university portal to view exam results.
● System Analyst
A System Analyst is a professional who analyzes and optimizes database systems to meet
business requirements. They act as a bridge between end-users, developers, and database
administrators (DBAs) to ensure that the database structure and applications are efficient and
effective.
Example: A System Analyst in a hospital designs a patient management system that stores
patient records efficiently and integrates with billing and lab systems.

● Sophisticated Users
A Sophisticated User is a database user who interacts with the DBMS directly using complex
queries and advanced tools rather than relying on predefined applications or forms. They have
a deep understanding of the database structure, SQL, and data analysis techniques.
Example: A Data Scientist querying large datasets for business insights
● Database Designers
A Database Designer is responsible for designing the structure of a database, ensuring it is
well-organized, efficient, and scalable. They define how data is stored, related, and accessed
based on business requirements.
Example: A database designer in an e-commerce company structures the database to store
customer details, orders, and inventory efficiently.

● Application programers
An Application Programmer is a software developer who writes programs that interact with a
database. They develop applications that allow users to store, retrieve, and manipulate data
without directly writing queries.
A banking application programmer develops an online banking system that allows customers
to check balances and transfer money through a user-friendly interface.

Database schema & Instance
Instance
It is the collection of information which is stored at a particular
moment
Schema
In a Database Management System (DBMS), the three-schema
architecture is a framework that describes the different levels of data
abstraction to separate the user view, the logical view, and the physical
view of the database.

Three Tier Schema Architecture

Physical Schema (Internal Schema)
The physical schema describes the how and where the data is physically
stored in the database. It defines the storage structures, file formats, and
disk organization that the Database Management System (DBMS) uses to
store data on physical storage devices like hard drives or solid-state drives
(SSDs).
In short, the physical schema focuses on how data is physically organized
and stored in the system, such as how tables, indexes, and other database
objects are stored on the disk.

Logical Schema (Conceptual Schema)
● This schema describes the logical structure of the entire
database.
● It defines what data is stored and the relationships among
the data. It is independent of how the data is physically
stored.
● It represents the database in a high-level abstract way.

View Level Schema (External level)
● The external schema defines the different views of the database for various users or
applications.
● It specifies how individual users or applications interact with the data. Multiple views can
be created, each showing only relevant information for different users.
● This level provides user-specific views and abstracts the complexity of the database
structure.

● The DBMS design depends upon its architecture. The basic client/server
architecture is used to deal with a large number of PCs, web servers,
database servers and other components that are connected with networks.
● The client/server architecture consists of many PCs and a workstation
which are connected via the network.
● DBMS architecture depends upon how users are connected to the
database to get their request done.

Types of DBMS Architecture
1-Tier Architecture
● In this architecture, the database is directly available to the user. It means the user can
directly sit on the DBMS and uses it.
● Any changes done here will directly be done on the database itself. It doesn't provide
a handy tool for end users.
● The 1-Tier architecture is used for development of the local application, where
programmers can directly communicate with the database for the quick response.

2-Tier Architecture
● The 2-Tier architecture is same as basic client-server. In the two-tier architecture,
applications on the client end can directly communicate with the database at the server
side. For this interaction, API's like: ODBC, JDBC are used.
● The user interfaces and application programs are run on the client-side.
● The server side is responsible to provide the functionalities like: query processing and
transaction management.
● To communicate with the DBMS, client-side application establishes a connection with
the server side.

3-Tier Architecture
● The 3-Tier architecture contains another layer between the client and server. In this
architecture, client can't directly communicate with the server.
● The application on the client-end interacts with an application server which further
communicates with the database system.
● End user has no idea about the existence of the database beyond the application server.
The database also has no idea about any other user beyond the application.
● The 3-Tier architecture is used in case of large web application.

Definition
Data independence can be explained using the three-schema architecture.
Data independence refers characteristic of being able to modify the schema at
one level of the database system without altering the schema at the next
higher level.
There are two types of data independence:
1. Logical Data Independence
2. Physical Data Independence

Logical Data Independence
● Logical data independence refers characteristic of being able to change the
conceptual schema without having to change the external schema.
● Logical data independence is used to separate the external level from the
conceptual view.
● If we do any changes in the conceptual view of the data, then the user view
of the data would not be affected.
● Logical data independence occurs at the user interface level.

Physical Data Independence
● Physical data independence can be defined as the capacity to change the
internal schema without having to change the conceptual schema.
● If we do any changes in the storage size of the database system server,
then the Conceptual structure of the database will not be affected.
● Physical data independence is used to separate conceptual levels from
the internal levels.
● Physical data independence occurs at the logical interface level.

Database Interfaces
Form-Based Interface
A form-based interface presents users with predefined forms (e.g., text boxes, dropdowns,
checkboxes) to input or display data. The user fills out fields in a form, and the interface
automatically maps the input to database fields (e.g., entering customer details in a "Customer
Information" form). After submission, the form sends the data to the database for insertion or
update. Its key features includes:
● Simple, structured data entry.
● Validation built into form fields to ensure correct data format.
● Predefined data types like dates, text, or numbers.
● Easy to use, especially for non-technical users.
● Reduces input errors by restricting data types and formats.

Example: A customer database with fields for "First Name," "Last Name," "Email," and "Phone Number."
Menu-Based Interface
A menu-based interface presents a list of options (menus) that users can select from to perform actions
such as querying, updating, or deleting data. Users navigate through a series of menus or submenus,
choosing commands or operations by clicking buttons or selecting options from a list. Its key features
includes:
● Easy navigation through menus and submenus.
● Limited flexibility, as actions are predefined in the menu options.
● Intuitive for non-technical users.
● Reduces errors as users are guided through predefined steps.

Graphical User Interface (GUI)
A GUI uses graphical elements like windows, buttons, icons, and tables for interacting with
the database. The user clicks on icons, buttons, or fields to perform database actions. GUI
tools typically allow for visual query building, data entry, and easy navigation. Its key features
includes:
● Visual representation of data, tables, and relationships.
● Query builders for creating SQL queries through drag-and-drop or form-based options.
● User-friendly and intuitive for non-technical users.

Natural Language Interface (NLI)
A Natural Language Interface allows users to interact with a database using natural language
(e.g., English) rather than SQL or other structured query languages. The user asks questions or
gives commands in natural language (e.g., “Show me all sales from last month”), and the
system uses Natural Language Processing (NLP) to interpret the query and generate the
corresponding SQL query to fetch data. Its key features includes:
● Users can ask questions in plain language, making database interaction accessible to non-
technical users.
● System converts natural language queries into structured queries (e.g., SQL).
● Makes querying the database more accessible to non-technical users.
● Allows users to directly ask for information without knowing SQL.

Speech Input/output Interface
Speech Input/output Interface allows users to interact with the database using voice
commands and receive voice-based responses. Users speak commands (e.g., "Show me all
orders for last week"), and the system processes the speech input using Speech Recognition
and executes the query. The results can be spoken back to the user via Text-to-Speech (TTS).
Its key features includes:
● Hands-free interaction with the database.
● Voice-driven commands and responses.
● Speech-to-text for input and text-to-speech for output.
● Convenient for users who prefer voice interaction or need hands-free access (e.g., while
driving or multitasking).
● Can be useful in customer support or virtual assistant applications.

Interface for Parametric Users
An interface for parametric users is designed for users who need to interact with a database
using parameters (e.g., dates, numerical ranges) to filter or search data. The user is presented
with fields to specify parameters (e.g., a date range, price range, etc.), and the database
fetches data based on these parameters. Its key features includes:
● Filters and parameters that allow users to narrow down data queries.
● Often used in applications where specific search criteria are needed (e.g., finding
products within a price range).
● Easy for users to get specific data based on defined parameters.
● Reduces complexity by limiting the data range and focusing on relevant results.

Interface for Database Administrators (DBA)
An interface for DBAs provides tools and functionalities tailored to the tasks that Database
Administrators need to perform. These interfaces typically include features for database
configuration, performance monitoring, backup management, user management, and
security administration. the functionality includes:
● Database Creation/Deletion:
● Table and Index Management
● Security Management
● Encryption
● Automated Backups:
● Database Logs

A Database Management System makes easier to create, maintain and work with the
databases. It acts as the channel between end users and the database enabling the
functions including administration, retrieval, updating and storing of data. By
structuring data into the organized formats and controlling concurrent access the
database management systems (DBMSs) contribute to the efficient handling,
security and integrity of data.
There are different fields where a database management system is utilized.
Following are a few applications that utilize the information base administration
framework.

Some Applications…….
1. Railway Reservation System
In the rail route reservation framework, the information base is needed to store the record or
information of ticket appointments, status of train’s appearance, and flight. Additionally, if
trains get late, individuals become acquainted with it through the information base update.
2. Library Management System
There are many books in the library so; it is difficult to store the record of the relative
multitude of books in a register or duplicate. Along these lines, the data set administration
framework (DBMS) is utilized to keep up all the data identified with the name of the book,
issue date, accessibility of the book, and its writer.
3. Banking
Database the executive’s framework is utilized to store the exchange data of the client in the
information base.

4. Education Sector
Presently, assessments are led online by numerous schools and colleges. They deal with all
assessment information through the data set administration framework (DBMS). In spite of
that understudy’s enlistments subtleties, grades, courses, expense, participation, results, and so
forth all the data is put away in the information base.
5. Credit card exchanges
The database Management framework is utilized for buying on charge cards and age of month
to month proclamations.
6. Social Media Sites
We all utilization of online media sites to associate with companions and to impart our
perspectives to the world. Every day, many people group pursue these online media accounts
like Pinterest, Facebook, Twitter, and Google in addition to. By the utilization of the data set
administration framework, all the data of clients are put away in the information base and, we
become ready to interface with others.

7. Broadcast communications
Without DBMS any media transmission organization can’t think. The Database the executive’s
framework is fundamental for these organizations to store the call subtleties and month to
month postpaid bills in the information base.
8. Accounting and Finance
The information base administration framework is utilized for putting away data about deals,
holding and acquisition of monetary instruments, for example, stocks and bonds in a data set.
9. E-Commerce Websites
These days, web-based shopping has become a major pattern. Nobody needs to visit the shop
and burn through their time. Everybody needs to shop through web based shopping sites, (for
example, Amazon, Flipkart, Snapdeal) from home. So all the items are sold and added
uniquely with the assistance of the information base administration framework (DBMS).
Receipt charges, installments, buy data these are finished with the assistance of DBMS.

10. Human Resource Management
Big firms or organizations have numerous specialists or representatives working under them.
They store data about worker’s compensation, assessment, and work with the assistance of an
information base administration framework (DBMS).
11. Manufacturing
Manufacturing organizations make various kinds of items and deal them consistently. To keep
the data about their items like bills, acquisition of the item, amount, inventory network the
executives, information base administration framework (DBMS) is utilized.
12. Airline Reservation System
This framework is equivalent to the railroad reservation framework. This framework
additionally utilizes an information base administration framework to store the records of
flight takeoff, appearance, and defer status.

13. Healthcare System
DBMS is used in healthcare to manage patient data, medical records, and billing
information.
14. Security
DBMS provides security features to ensure that only authorized users have access to
the data.
15. Telecommunication
Database Management Systems (DBMS) are essential to the telecommunications
industry because they manage enormous volumes of data on billing, customer
information, and network optimization.

Components in database environment
● Metadata
Metadata is information that describes the structure of the database. It includes details
about tables, columns, data types, relationships, constraints etc. It is stored in the DBMS
catalog (Data Dictionary) and helps the system understand how to handle data.
● Stored Database
The stored database contains the actual user data that is saved and managed in the DBMS.
It is the real records and values that users query, insert, update, or delete.

● Software to Access the Stored Data
This is the Database Management System (DBMS) that allows users to store, retrieve, update, and
delete data from the database. It provides an interface between users and the stored database.
Example: MySQL, Oracle, PostgreSQL, SQL Server
● Software to Process Queries (Query Processor)
The Query Processor is responsible for interpreting and executing user queries
(SQL commands). It includes the Query Parser, Query Optimizer, and Execution
Engine to ensure efficient query execution.
Example: When a user runs SELECT * FROM Students;, the query processor
optimizes and executes it to fetch the data.

Application Programs (Database Applications)
● These are custom-built software applications that interact with the database using queries.
● They provide a user-friendly interface for non-technical users to access and manipulate
data without writing SQL queries manually.
Example:
● Banking system application for money transfers.
● E-commerce websites that retrieve product details from a database.
● Student management system to view grades and attendance.

Classification of DBMS
A Data Model defines how data is structured, stored, and manipulated in a database. Based on
the data model, DBMS can be classified into
● Hierarchical Model
● Network Model
● Entity-Relationship Model
● Relational Model
● Object-Oriented Data Model
● Object-Relational Data Model
● Flat Data Model
● Context Data Model

Based on Distribution
a) Centralized DBMS: Single database stored in one location (server)
b) Distributed DBMS: Database is spread across multiple locations but appears as a single
database
Based on Users
c) Single-User DBMS: Only one user can access the database at a time.
d) Multiple users can access and modify data simultaneously.

Based on Access Method
OLTP (Online Transaction Processing)
● Used for real-time transactions (frequent read/write).
Example: Banking systems, E-commerce apps.
OLAP (Online Analytical Processing)
● Used for data analysis and reporting (large queries, less frequent updates).
Example: Data Warehouses, Business Intelligence systems.

DBMS_Chapter1_Introduction_to_database.pptx

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