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Introduction

MySQL is an open-source Relational Database Management System (RDBMS). It is used to store, organize, and manage data in a structured way using tables (rows & columns).

  • Relational Database → Data is stored in tables, and tables can be related to each other using primary keys and foreign keys.
  • SQL (Structured Query Language) → MySQL uses SQL to interact with data (e.g., SELECT, INSERT, UPDATE, DELETE).
  • Open Source → Free to use, with community and enterprise editions.
  • Cross-platform → Works on Windows, Linux, macOS.
  • Widely used → Powers many web applications like WordPress, Facebook (initially), YouTube, etc.
  • Client-server model → MySQL server handles database operations while clients (applications, users) interact with it via SQL.
  • ACID compliance (when using InnoDB engine) → Ensures data reliability and integrity in transactions.

Why Use MySQL?​

  1. Reliability & Stability
    • MySQL has been used for decades in production systems.
    • Known for stable performance even with large datasets.
  2. Ease of Use
    • Simple to install and configure.
    • SQL is a widely known language, so developers can quickly learn and use it.
  3. Open Source & Cost-effective
    • Completely free to use (community edition).
    • Enterprise editions with support are also available from Oracle.
  4. High Performance
    • Optimized for web applications that need to handle millions of queries daily.
    • Indexing, query optimization, and caching features improve speed.
  5. Cross-Platform & Integration
    • Works with many programming languages: PHP, Python, Java, C#, etc.
    • Runs on all major operating systems.
  6. Scalability
    • Can handle small projects (like a single-user application) as well as large, high-traffic websites.
  7. Security
    • Built-in user authentication, SSL support, and privileges system.

Questions​

  1. when using InnoDB engine ensures data reliability and integrity
  2. how to perform caching.
  3. practice cloud solutions
  4. how to define 1-1, 1-\*, \*-\* relationship with foreign ey
  5. constraint → Rules for the column (e.g., NOT NULL, UNIQUE, PRIMARY KEY). table_constraints → Constraints applied to the table as a whole (e.g., a PRIMARY KEY defined at the end).
  6. Be very careful — CASCADE can remove more than you expect.
  7. DECIMAL(10, 2) - what the value inserted for 3.5278 is it 3.52 or 3.53?
  8. how B tree work during indexing
  9. An index is a data structure that stores pointers to rows in a table, organized to make lookups faster.