← All projects

Data Layer

Model users and posts with Prisma and PostgreSQL.

Goal

This snapshot advances Meridian Notes by teaching you to model users and posts with Prisma and PostgreSQL.

Every numbered folder is a complete application. Run this stage on its own, then compare it with the previous snapshot to isolate the new responsibility.

Prerequisites

Use Node.js 20 or newer, npm, and a terminal. You should be comfortable with JavaScript functions, objects, modules, and basic HTML forms.

The development server uses port 3000. Data-backed snapshots use PostgreSQL on host port 5433 and keep their data in a database unique to that folder.

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

Concepts

Prisma turns a schema into a typed client. Relations connect each post to an author, while indexes support the reads later feed and ownership features need.

Keep the server boundary visible: Server Components may read trusted data directly, while Server Actions and route handlers must validate all incoming values and re-check authorization.

Walkthrough

Start PostgreSQL, copy the environment file, migrate the snapshot-specific database, seed Ada and Grace, and query posts in a dynamic Server Component.

Trace the example from request to rendered result, then inspect the matching snapshot for its surrounding types, validation, error handling, and configuration.

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

Run and verify

Enter 04-Data-Layer, install its dependencies, and copy .env.example when the snapshot includes one.

Open http://localhost:3000. Keep the terminal visible so framework, Prisma, and authentication errors can be matched to the browser action that caused them.

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

Troubleshooting

P1001 means Prisma cannot reach PostgreSQL. Confirm Docker health, port 5433, credentials, and the numbered database in DATABASE_URL.

A missing-module error usually means npm ran in another snapshot. Database errors often mean Docker is stopped, the environment file is missing, or this folder points at the wrong numbered database.

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

Try this

Add a draft post in Prisma Studio and decide whether the feed should include it.

Test one expected path and one invalid or unauthorized path. A production-minded app gives useful feedback without exposing secrets or stack traces.

  • Make one focused change
  • Verify it in the browser
  • Continue only after this snapshot works

Related tutorials