ShelfData AnalystData ScientistData EngineerSoftware Engineer (Backend)
SQL · Beginner · 3 h
Creating tables and changing data
Design tables with keys and constraints, then insert, update and delete rows safely inside transactions.
Why employers care: Analysts and engineers both load data and fix records. A wrong UPDATE without a WHERE is the classic production incident, and interviewers ask about keys, constraints and DELETE vs TRUNCATE.
In the roadmaps for: Data Analyst, Data Scientist, Data Engineer, Software Engineer (Backend)
Lessons, in order
- SQL CREATE TABLE with primary keys and foreign keysDesign real tables with primary keys, foreign keys, UNIQUE, CHECK and defaults in PostgreSQL, and watch each constraint stop bad rows from a messy retail export.17 min
- SQL INSERT, UPDATE and DELETE without breaking dataChange data the safe way: INSERT with RETURNING, UPDATE with a join, DELETE vs TRUNCATE vs DROP, and the preview, BEGIN, check, COMMIT routine, on real retail data.18 min