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Database basics

Database Basics: SQL vs NoSQL

A database is an organized collection of structured information, or data, typically stored electronically in a computer system.

1. Relational Databases (SQL)

  • Logic: Data is stored in Tables with rows and columns.
  • Relationships: Tables are linked using keys (Primary/Foreign).
  • Language: Uses SQL (Structured Query Language).
  • Examples: MySQL, PostgreSQL, SQLite, Oracle.
  • Analogy: A collection of interconnected Excel spreadsheets.

2. Non-Relational Databases (NoSQL)

  • Logic: Data is stored in Documents (like JSON objects).
  • Flexibility: Every document can have different fields.
  • Examples: MongoDB, Cassandra, Redis.
  • Analogy: A folder full of Word documents or JSON files.

Which one to use?

  • Use SQL for structured data with complex relationships (Bank systems, Accounting).
  • Use NoSQL for unstructured, rapidly changing data (Social media feeds, Real-time analytics).