Prisma ORM入門

Welcome to working with databases in Next.js! Often, you'll hear about an ORM, or Object-Relational Mapping. An ORM helps you interact with your database using your preferred programming language (like JavaScript/TypeScript) instead of writing raw SQL.

Prisma is a modern, open-source ORM that makes working with databases intuitive and type-safe. It's a fantastic tool for Next.js applications.

Prisma offers several key advantages for your Next.js projects:

• Type-Safety: It generates a type-safe client based on your database schema, catching errors at compile time.
• Developer Experience: Provides excellent auto-completion and readability for database queries.
• Migrations: Helps manage changes to your database schema over time in a controlled way.
• Modern Tooling: Integrates smoothly with modern JavaScript/TypeScript workflows and serverless environments.

Prisma isn't just one tool; it's a suite of tools that work together:

• Prisma Client: An auto-generated, type-safe query builder for your database. This is what you'll use in your code.
• Prisma Migrate: A migration system to evolve your database schema and keep it in sync with your Prisma schema.
• Prisma Studio: A visual GUI to view and edit data in your database.

Before we dive into setting up Prisma in your Next.js project, make sure you have these:

• An existing Next.js project (we'll assume you have one ready).
• Node.js and npm/yarn installed on your machine.
• A database. For local development, SQLite is easy to start with, or you can use PostgreSQL, MySQL, SQL Server, or MongoDB.

First, you need to install the Prisma CLI and the Prisma Client library as development dependencies in your Next.js project. Open your terminal in your project's root directory and run:

After installation, you'll initialize Prisma in your project. This command sets up the necessary files for Prisma to work. Run this in your terminal:

The npx prisma init command performs two important actions:

• It creates a new directory named prisma in your project root, containing a file called schema.prisma. This file defines your database schema.
• It creates a .env file in your project root. This file is used to store environment variables, most importantly your database connection URL.

The prisma/schema.prisma file is central to Prisma. It's where you define your database models and connection details. Here's what it looks like initially:

The .env file created earlier is where you'll specify your database connection string. For local development, you might use SQLite, which is file-based. Update your .env file to point to your database:

You've learned about Prisma's purpose and initial setup steps. Let's test your understanding!

In this lesson, we introduced Prisma ORM, understanding its role in bridging your application code with your database. We covered its key benefits like type-safety and improved developer experience, and explored its core components: Prisma Client, Migrate, and Studio.

You also learned the initial steps to integrate Prisma into a Next.js project, including installing the necessary packages and using npx prisma init to set up your schema.prisma and .env files. You're now ready to define your database schema!