Introduction to database management systems

Introduction to Databases: Definition of Data, Database, and DBMS, Overview of Database Applications, Advantages and Disadvantages of DBMS, Roles of Database Users and Administrators

1. DATABASE MANAGEMENT SYSTEM Unit - I

2. Database An organized collection of related data Stored and accessed electronically It is designed to efficiently manage, retrieve, and update data for various applications DBMS is the software that manages the database

3. Types of Database Users Database Administrators Database Designers Application Developers End Users Naive or Parametric Users Casual Users Sophisticated Users Standalone Users

4. Characteristics of the Database Approach Self-Describing Nature of a Database System Support for Multiple Views of Data Data Sharing and Multiuser Transaction Processing Centralized Data Management Controlled Redundancy Data Integrity Data Independence

5. Reduced Data Redundancy Improved Data Consistency Better Data Sharing Enhanced Data Security Data Integrity Enforcement Backup and Recovery Efficient Query Processing Multi-User Access and Concurrency Control Advantages of Using the DBMS Approach

6. Increased Cost Complexity Performance Frequency Upgrade/Replacement Cycles Damaged Part  Security Integrity Problems Disadvantages of DBMS

7. Importance of Data Models in DBMS Organized and Structured Data Ensuring Data Integrity and Consistency Facilitating Database Design and Development Enhancing Data Quality and Accuracy Optimizing Performance and Efficiency Scalability and Maintainability Supporting Informed Decision-Making

8. Introduction of ER Model

9. Keys Primary Key - Uniquely identifies each row in a table Must be unique. Cannot be NULL. One primary key per table . CREATE TABLE DEPARTMENT ( DeptID INT PRIMARY KEY , DeptName VARCHAR(50) );

10. Foreign Key Column (or set of columns) in one table that refers to the primary key in another table. It is used to create relationships between two tables. CREATE TABLE STUDENT ( StudentID INT PRIMARY KEY, Name VARCHAR(50), DeptID INT, FOREIGN KEY ( DeptID ) REFERENCES DEPARTMENT( DeptID ) );

11. Candidate Key column that can qualify as a primary key. A table can have multiple candidate keys. One is chosen as the primary key, and others remain as candidate keys. UNIQUE (Email),

12. Super Key A super key is any combination of columns that can uniquely identify a row in a table.

13. Composite Key A Composite Key is a primary key made up of two or more columns. It is used when no single column is unique by itself, but the combination of columns uniquely identifies each row. PRIMARY KEY ( StudentID , CourseID )

14. Alternate Key Unique Key Surrogate Key

15. Strong & Weak Entity Sets Strong entities have unique keys based on their own attributes While weak entities rely on relationships with other entities for unique identification