Next.js 15 Fullstack (App Router + Server Actions) · 课时

数据库架构迁移

使用 Prisma Migrate 管理数据库架构变更，实现顺畅的开发与部署

数据库架构迁移 是 CoddyKit 上的免费 Next.js 15 Fullstack (App Router + Server Actions) 课时。这是第 3 节课，共 4 节。你可以在下方免费阅读本课时的完整内容 — 然后在浏览器中使用内置代码编辑器和全天候 AI 导师进行实践。这是 Next.js 15 Fullstack (App Router + Server Actions) 学习路径的一部分，你的进度在网页和 CoddyKit 应用中同步。 Next.js 15 Fullstack (App Router + Server Actions) 课程共包含 4 节课。

本课时的部分内容尚未翻译，以英文显示。

What are Database Migrations?

As your application evolves, so does its database structure, also known as its schema.

Database migrations are like version control for your database schema. They are a way to manage changes to your database structure in a controlled and trackable manner.

They ensure your database matches your application's needs.
They prevent data loss during schema changes.
They provide a clear history of all schema modifications.

Why Use Prisma Migrate?

Managing database schema changes manually can be complex and error-prone. Prisma Migrate simplifies this process significantly.

Automatic Generation: It generates SQL migration files based on changes in your Prisma schema.
History Tracking: It keeps a history of applied migrations, making rollbacks and team collaboration easier.
Environment Consistency: Ensures your development, staging, and production databases all have the correct schema.

Your Prisma Schema File

Prisma Migrate uses your schema.prisma file as the source of truth for your database schema. Any changes you want to make to your database structure start here.

Let's recall a basic schema.prisma setup:

generator client {
  provider = "prisma-client-js"
}

datasource db {
  provider = "postgresql"
  url      = env("DATABASE_URL")
}

model User {
  id    Int     @id @default(autoincrement())
  name  String
  posts Post[]
}

model Post {
  id        Int      @id @default(autoincrement())
  title     String
  content   String?
  published Boolean  @default(false)
  author    User     @relation(fields: [authorId], references: [id])
  authorId  Int
}

Initializing Your First Migration

When you first set up your Prisma schema, you'll want to create an initial migration to apply this schema to your database. You use the prisma migrate dev command for this.

This command does two main things:

Generates a new migration file (SQL) in the prisma/migrations folder.
Applies the migration to your database.

npx prisma migrate dev --name initial_setup

Understanding Migration Files

After running npx prisma migrate dev, Prisma creates a new folder inside prisma/migrations with a timestamp and the name you provided (e.g., 20231026123456_initial_setup).

Inside this folder, you'll find:

migration.sql: This file contains the raw SQL commands generated by Prisma to create or alter your database tables.
migration.js or migration.ts: (If using TypeScript/JavaScript) Metadata about the migration.

It's important to commit these files to your version control system!

Making Schema Changes

Now, let's say you want to add an email field to your User model. You simply update your schema.prisma file.

Prisma will detect this change and help you generate a new migration.

model User {
  id    Int     @id @default(autoincrement())
  name  String
  email String  @unique // Added new field
  posts Post[]
}

Generating a New Migration

After modifying your schema.prisma, run npx prisma migrate dev again. Prisma will compare your updated schema with the current database state and generate a new migration file.

It will then apply this new migration, adding the email column to your User table.

npx prisma migrate dev --name add_user_email

Applying Migrations in Production

For production environments, you typically use npx prisma migrate deploy. This command applies all pending migrations that have not yet been run on the database.

Unlike migrate dev, deploy does not generate new migration files; it only applies existing ones. This makes it safe and predictable for production deployments.

npx prisma migrate deploy

Checking Migration Status

To see which migrations have been applied to your database and which are pending, you can use the npx prisma migrate status command.

This is useful for debugging or ensuring your database is up-to-date with your application's expected schema.

npx prisma migrate status

Prisma Migrate Commands Quiz

Which of the following statements correctly describe the purpose of Prisma Migrate commands?

Recap: Schema Migrations

Great job! You've learned how to manage your database schema effectively using Prisma Migrate.

Prisma Migrate helps version control your database schema.
You define schema changes in schema.prisma.
npx prisma migrate dev creates and applies migrations in development.
npx prisma migrate deploy applies existing migrations in production.
npx prisma migrate status checks the current migration state.

This powerful tool ensures your database structure stays consistent and aligned with your application's needs as it grows.

常见问题解答

「数据库架构迁移」课时是免费的吗？

是的 — 「数据库架构迁移」的完整文本可在网页上免费阅读。要进行交互式练习（内置代码编辑器和全天候 AI 导师）并解锁 Next.js 15 Fullstack (App Router + Server Actions) 课程的其余内容，请升级到 CoddyKit PRO。 Next.js 15 Fullstack (App Router + Server Actions) 课程共包含 4 节课。

「数据库架构迁移」这节课中我会学到什么？

使用 Prisma Migrate 管理数据库架构变更，实现顺畅的开发与部署你通过在浏览器中直接运行的动手代码来练习 Next.js 15 Fullstack (App Router + Server Actions)，全天候 AI 导师会在你学习这节课的过程中回答你的问题。

学习 Next.js 15 Fullstack (App Router + Server Actions) 需要有经验吗？

无需任何先前经验。CoddyKit 上的 Next.js 15 Fullstack (App Router + Server Actions) 课程适合初学者到高级学习者，你可以从这里开始或从头开始，按照自己的节奏学习。这是第 3 节课，共 4 节。

「数据库架构迁移」课时需要多长时间？

大多数 CoddyKit 课程大约需要 5–10 分钟。每节课都很精短且互动，所以你能稳步进步，并在网页和应用中从离开的地方继续。

我能在这节 Next.js 15 Fullstack (App Router + Server Actions) 课中编写并运行代码吗？

能。每节 Next.js 15 Fullstack (App Router + Server Actions) 课都包含内置代码编辑器，你可以在浏览器中直接编写并运行真实代码，并获得即时 AI 反馈 — 无需本地设置。

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