sql-lesson

name	sql-lesson
description	Produce or continue a SQL bootcamp lesson for dinotable, or review Zoha's submitted SQL/ERD work. Use when Zoha asks for the next SQL lesson, help with a SQL exercise, or review of schema/query work.

dinotable SQL bootcamp

Curriculum: the 8-lesson outline in docs/design/system-design.md §16 (tables/constraints → joins → normalization → indexes/EXPLAIN → transactions → locking → window functions/CTEs → migrations discipline). Lessons live in docs/sql-bootcamp/lesson-N-<slug>.md.

Two modes

Lesson mode (default when asked for "the next lesson"):

1. Check docs/sql-bootcamp/ for existing lessons; continue the sequence.
2. Every exercise uses the dinotable domain — Users, Restaurants, Branches, Tables, ServicePeriods, Slots, Reservations. Never use generic employees/departments examples.
3. Lesson structure:
   • Concept — the idea and the real problem it solves in this project
   • Setup — exact commands; a throwaway dockerized Postgres 16 (docker run --rm -e POSTGRES_PASSWORD=dev -p 5432:5432 postgres:16 plus psql via docker exec) so lessons work before the repo has any code. No installs on the host.
   • Guided exploration — queries to type and observe, with expected output
   • Exercises — 3–6, escalating difficulty, each framed as a real dinotable need ("the host needs tonight's reservations ordered by slot…")
   • Solutions — in a separate lesson-N-solutions.md, not inline. The lesson ends with: attempt everything before opening solutions.
4. Lessons 5 and 6 (transactions, locking) must include "break it on purpose": two concurrent psql sessions racing for the same slot, observing the anomaly, then fixing it.

Review mode (when Zoha shares SQL, a schema, or an ERD):

• Review like a senior reviewing a promising junior: ask questions before giving answers ("what happens if two rows have the same phone?" rather than "add a unique constraint").
• Point out what's right explicitly — calibration is part of teaching.
• Escalate: question → hint → concrete fix. Full corrected SQL only after Zoha has had a real attempt.
• Check the things juniors miss: constraint coverage, NULL semantics, index vs. query-shape mismatch, implicit assumptions about time zones.

Never write schema/migration files into the workspace (apps/, libs/) — all SQL lives in lesson docs until Zoha carries it into the project during a milestone.