FUNDAMENTALS FIRST
What is Data? Data = Raw facts without contextExample: “25”, “John”, “2024-12-21” What is Information? Information = Data with context/meaningExample: “John is 25 years old and joined on 2024-12-21” What is Database? Database = Organized collection of structured data stored electronically What is DBMS (Database Management System)? DBMS = Software to create, manage, and access […]
What is Data?
Data = Raw facts without context
Example: “25”, “John”, “2024-12-21”
What is Information?
Information = Data with context/meaning
Example: “John is 25 years old and joined on 2024-12-21”
What is Database?
Database = Organized collection of structured data stored electronically
- Eliminates data redundancy
- Ensures data integrity
- Enables concurrent access
- Provides security and backup
What is DBMS (Database Management System)?
DBMS = Software to create, manage, and access databases
Examples: Oracle, MySQL, PostgreSQL, SQL Server
What is RDBMS (Relational DBMS)?
RDBMS = DBMS based on relational model (tables with rows/columns)
- Uses SQL for data manipulation
- Enforces ACID properties (Atomicity, Consistency, Isolation, Durability)
- Oracle is an RDBMS
INTERVIEW QUESTIONS:
Q1: What’s the difference between data and database?
A: Data is raw facts. Database is an organized collection of related data stored systematically with relationships, constraints, and metadata for efficient retrieval and management.
Q2: Why use a database instead of flat files?
A: Databases provide:
- Data integrity through constraints
- Concurrent access control
- ACID transactions
- Efficient querying (indexes)
- Security and access control
- Backup/recovery mechanisms
- No data redundancy
Q3: What are ACID properties?
A:
- Atomicity: Transaction is all-or-nothing
- Consistency: Database moves from one valid state to another
- Isolation: Concurrent transactions don’t interfere
- Durability: Committed data survives system failures