CFA Unit-4_Database Management System.pdf, Study notes of Computer Fundamentals

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N O T E S ON:

CO MP UTER F U N DA MENTAL A N D

A P P L I C ATI ON

BCA 1

st

Semester

UNIT- 4 DATABASE MANAGEMENT SYSTEM o Introductions to data, database and DBMS o Database System Architecture o Database Model, database Application o SQL and No SQL concepts o Introduction to data warehousing o Data mining and concept of big data

Introduction to Data, Database & DBMS

 Information.

o Information is an organized collection of related data

which gives a complete sense.

For eg: “Ram is a student , He is 20 years old”.

Data Processing Information

Introduction to Data, Database & DBMS  Data Vs. Information o Data is raw facts and figures, whereas Information is processed and meaningful data. o Data is unorganized, whereas Information is organized. o Data has no clear meaning by itself, whereas Information gives meaningful understanding. o Data is used as input, whereas Information is the output after processing. o Data is used for processing, whereas Information is used for decision- making. o Data comes before processing, whereas Information comes after processing. o Example: Data = 10, 20, 30; Information = Average = 20.

Introduction to Data, Database & DBMS  Database management system o Database(Collection of data) + management system( is a set of program to store and retrieve these data.) o A database management system (DBMS) is the software that allows a computer to perform database function of storing, retrieving, adding, deleting, update and modifying data. o It allows users to easily add, update, delete, and retrieve data while ensuring data security, consistency, and integrity. o Examples of DBMS include MySQL, Oracle Database, and Microsoft Access.

Advantages of Database Management System (DBMS)

1. Data Security: DBMS improves data security using access control and encryption. It prevents unauthorized access and protects user privacy. 2. Data Integration: It combines data from different sources into one centralized system, giving a complete organizational view. 3. Data Abstraction: Complex database operations are hidden from users through different abstraction levels, making the system easy to use. 4. Reduction in Data Redundancy: DBMS reduces duplicate data by applying constraints, saving storage space and improving consistency. Example: Duplicate student records can be removed. 5. Data Sharing: Multiple users and applications can access and share data easily, improving collaboration and productivity.

Disadvantages of Database management system o High Cost: Expensive software, hardware, and memory needed. o Large Size: Very big databases may slow performance. o Database Failure: Centralized failure can lead to data loss. o Complexity: Difficult for non-technical users. o Staff Costs: Skilled personnel needed, increasing expenses. o Data Conversion Cost: Migrating old data is costly. o Performance Issues: Complex operations may reduce speed.

Application areas of Database management system o Banking Systems: Managing accounts, transactions, loans, and customer information. o Educational Institutions: Storing student records, courses, grades, and staff details. o Airline Reservation Systems: Managing flight schedules, bookings, and ticketing. o Library Management: Tracking books, members, loans, and returns. o Hospital Management: Patient records, appointments, billing, and medical history. o Business and Retail: Inventory management, sales, customer data, and supply chain tracking. o Government Agencies: Maintaining citizen records, tax data, and legal documentation. o Telecommunication: Storing subscriber information, billing, and usage data. o E-commerce: Managing product catalogs, orders, customers, and payments. o Research Organizations: Storing experimental data, results, and publications.

DBMS vs file system

DBMS vs file system (continue…)

Database System Architecture o The typical structure of DBMS is based on Relational data model. o The top part of the architecture shows application interfaces used by naive users, application programs created by application programmers, query tools used by sophisticated users and administration tools used by database administrator. o The lowest part of the architecture is for disk storage. o The Middle two parts(Query processor and storage manager) are important components of database architecture.

Database System Architecture

 Query processor:

o The interactive query processor helps the database system

to simplify and facilitate access to data.

o The query processor handles interpreting and executing

user queries.

o The following are various functionalities and components of

query processor:

 DDL(Data Definition Language) interpreter,

 DML(Data Manipulation Language) compiler and

 Query evaluation engine

Database System Architecture  Storage manager: o Storage manager is the component of database system that provides interface between the low level data stored in the database and the application programs and queries submitted to the system. o The storage manager is responsible for storing, retrieving, and updating data in the database. The storage manager components include: o Authorization and integrity manager: Validates the users who want to access the data and tests for integrity constraints. o Transaction manager: Ensures that the database remains in consistent despite of system failures and concurrent transaction execution proceeds without conflicting.

Database System Architecture o File manager: Manages allocation of space on disk storage and data structures used to represent the information stored on disk. o Buffer manager: Manages the fetching of data from disk storage into main memory. The buffer manager also decides what data to cache in main memory. Buffer manager is a crucial part of database system, since it enables the database to handle data sizes that are much larger than the size of main memory. Storage manager implements several data structures such as:  Data files: Used for storing database itself.  Data dictionary: Used for storing metadata about the structure of database, particularly schema of database.  Indices: Indices are used to provide fast access to data items present in the database