Databases 101 for PMs

Summary

A basic mental model of tables, rows and relationships — enough to understand why 'just add one field' isn't always trivial, and to ask informed questions about data migrations.

• 1Sketch a simple database schema (e.g. users, posts, comments) for an app you use.
• 2Learn the difference between a relational (SQL) and non-relational (NoSQL) database at a high level.
• 3Understand why changing an existing field's type can be a risky migration, not a quick fix.