02 Model the data · Instructor

Timing

20 minutes.

Talk track

• Query patterns come before ORDER BY; the key cannot be casually changed later.
• Exact decimals avoid floating-point money/probability artifacts.
• Recent-time expressions lead the event keys; token/condition IDs follow for grouping.
• The incremental MV aggregates only BBO midpoint events. Trades remain separate.
• No partition is intentional; this track has no demonstrated retention lifecycle.

Common failures

• Partial run: all statements use IF NOT EXISTS; rerun the complete blocks.
• MV exists but target does not: drop only the MV, rerun Step 2.
• Learner uses a different database: verify .env.polymarket says polymarket.

Reset

For a disposable rehearsal only:

DROP DATABASE IF EXISTS polymarket;

Then rerun both learner SQL blocks. Never run this against a learner's service without their explicit confirmation.