两个棱镜模型之间的一对多和多对多关系

Question

我正在做一个副项目，遇到了一个我不确定如何解决的问题。我创建了两个模型，一个用于用户，一个用于项目。它们之间的关系是多对多的，因为一个用户可以有多个项目，但我还想在项目模型中添加一个createdBy，这应该是一对一的，因为每个项目只能有一个用户谁创造了它。这是我的模型的样子：

model User {
  id            String         @id @default(cuid())
  name          String?
  email         String?        @unique
  emailVerified DateTime?
  image         String?
  createdAt     DateTime       @default(now())
  updatedAt     DateTime       @updatedAt
  accounts      Account[]
  sessions      Session[]
  projects      Project[]
  Project       Project[]      @relation("userId")
}

model Project {
  id             Int          @id @default(autoincrement())
  createdAt      DateTime     @default(now())
  name           String
  favourite      Boolean      @default(false)
  archived       Boolean      @default(false)
  users          User[]
  about          String?
  archivedAt     String?
  deletedAt      String?
  createdBy      User         @relation("userId", fields: [userId], references: [id])
  userId         String
}

从 prisma migrate dev 得到的错误是

Step 1 Added the required column userId to the Project table without a default value. There are 2 rows in this table, it is not possible to execute this step.

不确定我做错了什么，因为我几乎是一个数据库建模新手。任何帮助将不胜感激。

Answer 1

要使用 One-To-Many 实现 Many-to-Many，您需要将 schema.prisma 文件设置为：

model User {
  id            String    @id @default(cuid())
  name          String?
  email         String?   @unique
  emailVerified DateTime?
  image         String?
  createdAt     DateTime  @default(now())
  updatedAt     DateTime  @updatedAt

  projects Project[]

  userProjects UserProjects[]
}

model Project {
  id         Int      @id @default(autoincrement())
  createdAt  DateTime @default(now())
  name       String
  favourite  Boolean  @default(false)
  archived   Boolean  @default(false)
  about      String?
  archivedAt String?
  deletedAt  String?

  createdBy User   @relation(fields: [user_id], references: [id])
  user_id   String

  projectUsers UserProjects[]
}

model UserProjects {
  project    Project @relation(fields: [project_id], references: [id])
  project_id Int
  user       User    @relation(fields: [user_id], references: [id])
  user_id    String

  @@id([project_id, user_id])
}

应该迁移成功。

两个棱镜模型之间的一对多和多对多关系

One-to-many and may-to-many relation between two prisma model

prisma

prisma2

plumatic-schema