prisma-database-setup-mongodb

# MongoDB Setup **⚠️ WARNING: MongoDB is NOT supported in Prisma ORM v7.** Support for MongoDB is planned for a future v7 release. If you need MongoDB, you must use **Prisma ORM v6**. ## Prerequisites - MongoDB 4.2+ - Replica Set configured (required for transactions) - **Prisma ORM v6.x** ## 1. Schema Configuration (v6) In `prisma/schema.prisma`: ```prisma datasource db { provider = "mongodb" url = env("DATABASE_URL") } generator client { provider = "prisma-client-js" } ``` ### ID Field Requirement MongoDB models **must** have a mapped `_id` field using `@id` and `@map("_id")`, usually of type `String` with `auto()` and `db.ObjectId`. ```prisma model User { id String @id @default(auto()) @map("_id") @db.ObjectId email String @unique name String? } ``` ### Relations Relations in MongoDB expect IDs to be `db.ObjectId` type. ```prisma model Post { id String @id @default(auto()) @map("_id") @db.ObjectId author User @relation(fields: [authorId], references: [id]) authorId String @db.ObjectId } ``` ## 2. Environment Variable In `.env`: ```env DATABASE_URL="mongodb+srv://user:password@cluster.mongodb.net/mydb?retryWrites=true&w=majority" ``` ## Migrations vs Introspection - **No Migrations**: MongoDB is schema-less. `prisma migrate` commands **do not work**. - **db push**: Use `prisma db push` to sync indexes and constraints. - **db pull**: Use `prisma db pull` to generate schema from existing data (sampling). ## Common Issues ### "Transactions not supported" Ensure your MongoDB instance is a **Replica Set**. Standalone instances do not support transactions. Atlas clusters are replica sets by default. ### "Invalid ObjectID" Ensure fields referencing IDs are decorated with `@db.ObjectId` if the target is an ObjectID.