DATABASE MANAGEMENT SYSTEMS UNIT ONE - TOPIC ONE INTRODUCTION TO DBMS

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DATABASE MANAGEMENT SYSTEMS UNIT ONE - TOPIC ONE INTRODUCTION TO DBMS

Database

A database is a collection of data, typically describing the activities of one or more related organizations.

Example: a university database might contain information about the following:

Entities such as students, faculty, courses, and classrooms.

Relationships between entities, such as students' enrollment in courses, faculty teaching courses, and the use of rooms for courses.

Database Management System (DBMS)

A database management system, or DBMS, is software designed to assist in maintaining and utilizing large collections of data.

The alternative to using a DBMS is to store the data in files and write application-specific code to manage it.

A Historical Perspective or History of Database Systems

FILE SYSTEMS VERSUS DBMS

Database Management System (DBMS)

ADVANTAGES OF A DBMS

Database System Applications

DATABASE MANAGEMENT SYSTEMS UNIT ONE - TOPIC TWO DATA MODELS

Data model types

Hierarchical Model

Network Model

Relational model

Entity-Relationship Model

Object-Oriented Data Model

DATABASE MANAGEMENT SYSTEMS UNIT ONE - TOPIC THREE LEVELS OF ABSTRACTION AND DATA INDEPENDENCE

View level / External View: (Who)

Benefits of Levels of Abstraction in DBMS

Data Independence

DATABASE MANAGEMENT SYSTEMS UNIT ONE - TOPIC FOUR STRUCTURE OF DBMS

One. Query Processor:

Query Processor contains the following components

Two. Storage Manager:

It contains the following components -

Three. Disk Storage:

Types of Database Users

Two. Database Designers:

Three. System Analyst:

Four. Application Programmers:

Five. Naïve Users / Parametric Users:

Six. Sophisticated Users:

Seven. Casual Users / Temporary Users:

Data as a Corporate Asset:

Role of a Database in an Organization:

DataBase Administration Function:

DBA skills are be divided into two categories Managerial Role Technical Role

One. End-User Support

Two. Policies, Procedures and Standards

Three. Data Security, Privacy and Integrity

Four. Data Backup and Recovery

The DBA's Technical Role

The technical aspects of the DBA's job are rooted in the following areas of operation:

Two. Designing and implementing databases and applications.

Three. Testing and evaluating databases and applications.

Four. Operating the DBMS, utilities, and applications.

Five. Training and supporting users.

Six. Maintaining the DBMS, utilities, and applications.

Database design is the set of procedures or collection of tasks used for organizing the data to implement a database.

The database design process can be divided into six steps. The ER model is most relevant to the first three steps.

Entity-Relationship Model:

History of ER models

Components of ER Diagram:

- Examples:

Strong Entity

Example - Strong Entity Set

ATTRIBUTES

Example:

Attributes are represented with ellipse

Four. Single-valued attribute: As the name suggests, they have a single value.

Relationship

ER - Relationships

DATABASE MANAGEMENT SYSTEMS Database Design and ER Model

Types:

One. Unary Relationship

Two. Binary Relationship

One to One Relationship

Many to One Relationship

Many to Many Relationships

Three. Ternary Relationship

ADDITIONAL FEATURES OF THE ER MODEL

One. Generalization -

Two. Specialization -

Three. Aggregation:

Participation Constraints:

Types of Participation Constraints:

One. Total Participation

Two. Partial Participation

DATABASE MANAGEMENT SYSTEMS Conceptual Design Using the ER Model

One. Entity vs. Attribute

Two. Entity versus Relationship

Three. Binary versus Ternary Relationships

Four. Aggregation versus Ternary relationship

DATABASE MANAGEMENT SYSTEMS SQL - DATA DEFINITION LANGUAGE

Types of SQL Commands:

Data Definition Language

Data Query Language

Transaction Control Language

CREATE:

Syntax: CREATE Object type Object name;

Syntax: create database database name;

Syntax: SHOW DATABASES;

Creating a Table:

Create Table using Another Table:

Data Types in MySQL:

String Data Type:

Date and Time Data Type:

To drop a Table

To drop a database

TRUNCATE:

Syntax:

Example:

ALTER:

ALTER- ADD ALTER- MODIFY ALTER-DROP

Syntax:

To Drop a column from an existing table:

Ex: alter table emp drop column mobile; To modify a column in the Table:

ALTER TABLE table_name MODIFY columnname-1 datatype(size);

Syntax:

RENAME:

Renaming the column name in an existing table:

DATABASE MANAGEMENT SYSTEMS DATA MANIPULATION LANGUAGE

NOTE:

What is SQL Process?

What is Advantages of SQL?

DATA MANIPULATION LANGUAGE

DDL vs DML Commands

One. INSERT

Syntax:

Example:

Syntax:

Example:

Syntax:

Example:

Syntax

INSERT INTO table2

Example:

Two. UPDATE

Syntax:

Example:

Three. DELETE

Example:

Four. SELECT

Syntax:

Examples:

Example: select * from employee;

Syntax to select selected rows and selected columns:

Example:

DATABASE MANAGEMENT SYSTEMS Transaction Control Language (TCL) Commands

TCL Commands - Save point Commit and Roll back:

ROLLBACK command:

SAVEPOINT command:

Example: Using Savepoint and Rollback:

DATABASE MANAGEMENT SYSTEMS Data Control Language

· GRANT

Grant Privileges on Table

Syntax

Object

User_account_name

Example

Revoke Privileges on Table:

Syntax

REVOKE privileges ON object FROM user_account_name;

Let's look at some examples of how to revoke privileges on tables in SQL Server.

Differences between Grant and Revoke commands:

Disadvantages of DCL commands:

Overview

This document explains the basics of Database Management Systems, including their functions and benefits, the evolution of data models, and the essential applications of DBMS in sectors like education, banking, and online shopping. It also explores the levels of abstraction in DBMS and the concept of data independence.

Key Points

1DBMS is crucial for managing data efficiently and securely
2The relational model is the most widely used data model today
3Data independence is vital for separating data from application programs
4Common DBMS applications include telecom, education, and banking systems
5Understanding levels of data abstraction helps users interact with databases effectively

Details

Category: Technology and Engineering

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