EO Engineering Learning OS
PROJECT LADDER · P01
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CORE PROJECT · TARGET L2–3 · 3–5 days
P01

Local application

Establish the browser → FastAPI → database mental model using one working application.

01 / CONCEPT MAP

Know what the parts mean.

Learn each concept deeply enough to recognize it, place it in the system and reason about normal and failed behavior.

01

Frontend/backend flow

Define it · locate it · observe it · explain its failure mode.

02

FastAPI routes

Define it · locate it · observe it · explain its failure mode.

03

SQLite and MySQL

Define it · locate it · observe it · explain its failure mode.

04

Schemas and SQL

Define it · locate it · observe it · explain its failure mode.

05

Configuration

Define it · locate it · observe it · explain its failure mode.

02 / SYSTEM FLOW

Trace it end to end.

Browser→Frontend→FastAPI→SQL→SQLite / MySQL→response

For every transition: identify input, output, identity, protocol, state, trust boundary, evidence and owner.

03 / GUIDED BUILD

Build, observe and explain.

Documentation and AI are allowed. The engineer must review every output and demonstrate the result from direct evidence.

  1. 01Run the supplied app locally
  2. 02Trace one create and list request
  3. 03Inspect the schema
  4. 04Migrate from SQLite to MySQL
  5. 05Fix a deliberate schema mismatch
  6. 06Document the full flow
04 / INCIDENT

The API starts but fails on insert because the application and database schemas disagree.

Required investigation

State impact → collect evidence → form competing hypotheses → test the cheapest discriminator → isolate root cause → contain → correct → verify.

Evidence pack

Timeline, relevant logs/metrics, failed assumptions, root cause, correction, verification and one prevention action.

AI ownership

AI may suggest causes and commands. The engineer must explain why each check is safe, what result is expected and how the result changes the hypothesis.

05 / DESIGN CHALLENGE

Defend the decision.

Explain what changes—and what should not—when the database engine changes.

06 / VERIFY, SUBMIT & REVIEW

Submission evidence

Architecture review

  • Explain local application without relying on memorized commands.
  • Draw the flow and name what crosses every arrow.
  • Identify the most likely, highest-impact and hardest-to-detect failure.
  • Show the evidence that proves the solution works.
  • Defend one security, reliability and cost trade-off.

Definition of Done

  • Acceptance criteria pass
  • Flow is drawn and explained
  • Security implications considered
  • Logs/metrics checked
  • Failure is tested
  • AI output is understood
  • Runbook is reusable
  • Mentor review passes
07 / MENTOR GUIDE

Do not score memory. Score the engineer’s ability to form a model, collect evidence, make a safe change and defend the trade-off.

1 Cannot explain2 Understands with gaps3 Implements and troubleshoots4 Designs and reviews