DBMS_Unit1
Course Overview
IILM University offers a course titled Data Base Management System (UCS2001) led by Pulkit Dwivedi. This course is structured to facilitate comprehensive learning of database concepts and tools.
Course Outcomes
At the conclusion of this course, students will be expected to:
CO1: Understand database design methodology and create ER-models for basic applications.
CO2: Apply query processing techniques in real-time database problems.
CO3: Identify and resolve redundancy in database tables using normalization techniques.
CO4: Grasp the concepts of transactions, their processing, and a variety of management issues like data integrity, security, and recovery.
CO5: Comprehend concurrency control protocols and recovery algorithms, ultimately implementing a small database project using appropriate tools.
Recommended Textbooks
Database Concepts by Korth, Silbertz, Sudarshan (McGraw Hill)
Fundamentals of Database Systems by Elmasri, Navathe (Addison Wesley)
Database Management Systems by Ramakrishnan (McGraw Hill)
Reference Books
An Introduction to Database Systems by Date C J (Addison Wesley)
Database Management System by Majumdar and Bhattacharya (TMH)
Unit 1: Introduction to DBMS
Topics Covered
Database and DBMS Introduction
Comparison: Database System vs File System
Database System Architecture
Data Models
Overall Database System Structure
ER Model Concepts and Notations
Mapping Constraints
Keys
Generalization, Aggregation, Specialization
Conversion of ER Diagram to Tables
Definitions
Data
Raw, unprocessed facts and figures collected for analysis. Examples include numbers, words, measurements, and observations.
Information
Processed data that has been organized to provide meaning and context (e.g., average age).
Database
A structured collection of related data that allows for easy access and management.
Database Management System (DBMS)
A software solution for creating and managing databases, enabling users to store, process, and analyze data effectively. DBMS offers protection, security, and consistency in multi-user environments.
Examples of DBMS
MySQL, Oracle, SQL Server, IBM DB2, PostgreSQL, Amazon SimpleDB.
Database System vs File System Comparison
Aspect | File System | Database System |
---|---|---|
Purpose | Store and organize files | Store, manage, retrieve structured data |
Structure | Hierarchical with directories | Tabular (tables, rows, columns) |
Access | File paths | SQL or other query languages |
Complexity | Simple operations | Complex operations |
Examples | Windows File System, NTFS | MySQL, PostgreSQL |
Usage Scenarios | General file storage | Enterprise applications |
Characteristics of DBMS
Data stored in tables, reduced redundancy, data consistency, multi-user support, query language, security features.
Advantages of DBMS
Minimizes data redundancy and allows for easy data retrieval. Enables quick data integration into various applications and offers cloud storage capabilities.
Disadvantages of DBMS
Complexity in management, costs associated with licensed DBMS, and larger system sizes.
Components of DBMS
Hardware
Physical components like computers, hard disks, and input/output channels necessary for storing and accessing data.
Software
The core program that facilitates all operations and user interactions with the database.
Data
The primary resource that DBMS manages, including both user data and metadata (data about data).
Procedures
General instructions for using the DBMS, including setup, user management, and report generation.
Database Access Language
A specialized language used to interact with the database for operations like querying, updating, and deleting data.
Users of DBMS
Database Administrators (DBA): Manage security, licenses, and user access.
Application Programmers: Develop and design DBMS components.
End Users: Perform operations to store, retrieve, and modify data.
DBMS Architectures
Single-Tier Architecture
All components reside on a single server, best for individual access where changes are infrequent.
Two-Tier Architecture
Client-server model allowing multiple users to access the database. Improved performance and maintainability.
Three-Tier Architecture
Involves a middle application layer that interacts with both client and servers, enhancing security and integrity while increasing complexity.
Data Models in DBMS
Help visualize the logical structure through symbols and text for effective database design. Types include:
Hierarchical Model
Network Model
Entity-Relationship (ER) Model
Relational Model
Object-Oriented Model
Object-Relational Model
Entity-Relationship Model (ER) Overview
ER diagrams indicate the structure of a database, depicting entities (independent objects with attributes) and their relationships.
Key Components of ER Diagrams
Entities: Independent objects (e.g., Employee, Company).
Attributes: Characteristics (e.g., Employee ID).
Relationships: Connections between entities (e.g., "works in").
Types of Relationships
One-to-One, One-to-Many, Many-to-One, and Many-to-Many relationships illustrate how entities interact.
Keys in DBMS
Types of Keys
Super Key: Any combination of attributes that uniquely identifies records.
Candidate Key: Minimal set of attributes required for uniqueness.
Primary Key: A specific candidate key chosen for uniqueness and non-null requirement.
Alternate Key: Candidate keys not chosen as a primary key.
Foreign Key: Refers to primary key in another table.
Composite Key: Formed by combining multiple columns.
Surrogate Key: Artificially generated key for uniqueness.
Summary of Keys Characteristics
Business logic, uniqueness, and referential integrity are vital in identifying records and maintaining consistency.