Document composite keys in the find/update/delete sections of the docs

[nikolasburk]

As requested here: prisma/prisma-client-js#488 (comment)

[pkellner]

I'm having the same issue in mysql, but can't figure out how to reference the composite key to delete. My workaround is I'm going to add an artificial key to my link table which really should not need one.

Below is the mysql create and my model

CREATE TABLE `NoteOnTag` (
  `noteId` int NOT NULL,
  `tagId` int NOT NULL,
  `createdAt` datetime(3) NOT NULL DEFAULT CURRENT_TIMESTAMP(3),
  PRIMARY KEY (`noteId`,`tagId`),
  KEY `tagId` (`tagId`),
  CONSTRAINT `noteontag_ibfk_1` FOREIGN KEY (`noteId`) REFERENCES `Note` (`id`) ON DELETE RESTRICT ON UPDATE CASCADE,
  CONSTRAINT `noteontag_ibfk_2` FOREIGN KEY (`tagId`) REFERENCES `Tag` (`id`) ON DELETE RESTRICT ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci

model Note {
  id             Int             @id @default(autoincrement())
  title          String          @db.VarChar(128)
  description    String?         @db.VarChar(1024)
  createDate     DateTime        @db.DateTime(0)
  active         Int             @db.TinyInt
  noteChangeLogs NoteChangeLog[]
  noteAttributes NoteAttributes?
  noteOnTags     NoteOnTag[]
}



model Tag {
  id         Int          @id @default(autoincrement())
  tagName    String       @db.VarChar(32)
  noteOnTags NoteOnTag[]
}

model NoteOnTag {
  note      Note     @relation(fields: [noteId], references: [id])
  noteId    Int
  tag       Tag      @relation(fields: [tagId], references: [id])
  tagId     Int
  createdAt DateTime @default(now())

  @@id([noteId, tagId])
}

[ruheni]

We're currently working on this. You can find the PR here: #4591