Lesson 16 · Python
Databases: SQL Fundamentals
Meet relational databases through SQLite: why they beat JSON files, how to create typed tables, and how to ask precise questions with SELECT, WHERE, ORDER BY, and LIMIT.
Prerequisites: Data Structures: Trees & Graphs
Learning objectives
By the end of this lesson, you will be able to:
- Explain what a database gives you over a JSON file: safe concurrency, enforced integrity, and querying without loading everything
- Create a table with CREATE TABLE and sensible column types
- Add rows with INSERT and read them back with SELECT, WHERE, ORDER BY, and LIMIT
- Write correct queries against NULL values with IS NULL and IS NOT NULL
- Open and explore a SQLite database file with the sqlite3 CLI and DB Browser