Database Fundamentals

What is a Database?

A database is an organized collection of structured information, or data, typically stored electronically in a computer system. A database is usually controlled by a database management system (DBMS).

Key Concepts

Data vs. Information

• Data: Raw facts and figures
• Information: Processed data that has meaning and context

Database Management System (DBMS)

A software system that enables users to define, create, maintain, and control access to databases.

Database Models

• Hierarchical Model: Tree-like structure
• Network Model: Graph structure with multiple parent-child relationships
• Relational Model: Data organized in tables (most common)
• Object-Oriented Model: Data stored as objects

Advantages of Databases

• Data Integrity: Ensures data accuracy and consistency
• Data Security: Controls access to sensitive information
• Data Redundancy Control: Minimizes duplicate data
• Data Independence: Separates data from applications
• Concurrent Access: Multiple users can access data simultaneously

Database Users

• Database Administrators (DBAs): Manage and maintain databases
• Database Designers: Design database structure and schema
• Application Programmers: Develop applications that use databases
• End Users: Use database applications to access data

ACID Properties

• Atomicity: All operations in a transaction succeed or fail together
• Consistency: Database remains in a valid state after transactions
• Isolation: Concurrent transactions don’t interfere with each other
• Durability: Committed transactions persist even after system failure