Data Layer

Goal

This snapshot advances Tidepool Notes by teaching you to persist authors and posts with Prisma and PostgreSQL.

Every numbered folder is a complete app. Run this stage independently, then compare it with the previous folder.

Prerequisites

Use Node.js 20+, npm, and a terminal. You should recognize React components, TypeScript modules, and HTTP verbs.

Port 3004 must be free. Copy .env.example before starting database stages.

• Node.js and npm
• A code editor and terminal
• Docker from part 4 onward

Concepts

Prisma schema files define tables with relations. Each snapshot uses its own tidepool database so stages stay independent.

Keep the server boundary visible: Remix loaders read trusted data on the server; actions must validate input and re-check authorization before mutations.

Walkthrough

Connect DATABASE_URL, define User and Post models, seed Ada and Grace, and list posts in the home loader.

Read the example, then open the matching snapshot. The repository includes the surrounding setup and error handling.

const posts = await prisma.post.findMany({ include: { author: true }, orderBy: { createdAt: "desc" } })

Run and verify

Enter 04-Data-Layer, install dependencies, copy .env.example when present, and start Remix on port 3004.

Open http://127.0.0.1:3004. Watch the terminal for validation and database errors.

docker compose -f ../docker-compose.yml up -d
git clone https://github.com/michaeldunga1/fcc-remix-blog.git
cd fcc-remix-blog/04-Data-Layer
npm install
cp .env.example .env
npm run db:push
npm run db:seed
npm run dev

Troubleshooting

Connection refused usually means Docker Postgres is stopped or the port is not 5442.

Missing-module errors usually mean npm install ran in another snapshot. For Postgres failures, confirm Docker and the tidepool_NN database name.

• Read the first error first
• Restart after environment changes
• Never commit .env or node_modules

Try this

Add a minimum title length check before insert.

Test a happy path and one invalid or unauthorized request.

• Make one small change
• Test it in the browser
• Compare with the next snapshot only after it works