NestJS with Nx, Prisma ORM, MariaDB Database, and GraphQL API

Initialize NestJS Shared Library for “model” with Prisma Support

Reference:

yarn add --dev prisma

nx g @nrwl/nest:library model
cd libs/model
../../node_modules/.bin/prisma init

Edit workspace.json and add the following targets into “model” project:

        "prisma-generate": {
          "executor": "@nrwl/workspace:run-commands",
          "outputs": [],
          "options": {
            "command": "../../node_modules/.bin/prisma generate",
            "cwd": "libs/model"
          }
        },
        "migrate-save": {
          "executor": "@nrwl/workspace:run-commands",
          "outputs": [],
          "options": {
            "command": "../../node_modules/.bin/prisma migrate dev --create-only --preview-feature --schema ./prisma/schema.prisma",
            "cwd": "libs/model"
          }
        },
        "migrate-up": {
          "executor": "@nrwl/workspace:run-commands",
          "outputs": [],
          "options": {
            "command": "../../node_modules/.bin/prisma migrate dev --preview-feature --schema ./prisma/schema.prisma",
            "cwd": "libs/model"
          }
        },
        "migrate-reset": {
          "executor": "@nrwl/workspace:run-commands",
          "outputs": [],
          "options": {
            "command": "../../node_modules/.bin/prisma migrate reset --preview-feature --schema ./prisma/schema.prisma",
            "cwd": "libs/model"
          }
        },
        "migrate-deploy": {
          "executor": "@nrwl/workspace:run-commands",
          "outputs": [],
          "options": {
            "command": "../../node_modules/.bin/prisma migrate deploy --preview-feature --schema ./prisma/schema.prisma",
            "cwd": "libs/model"
          }
        },
        "migrate-status": {
          "executor": "@nrwl/workspace:run-commands",
          "outputs": [],
          "options": {
            "command": "../../node_modules/.bin/prisma migrate status --preview-feature --schema ./prisma/schema.prisma",
            "cwd": "libs/model"
          }
        },
        "studio": {
          "executor": "@nrwl/workspace:run-commands",
          "outputs": [],
          "options": {
            "command": "../../node_modules/.bin/prisma studio --schema ./prisma/schema.prisma",
            "cwd": "libs/model"
          }
        }

schema.prisma File

Before you edit, it’s a good idea to install Prisma extension for VS Code.

// This is your Prisma schema file,
// learn more about it in the docs: https://pris.ly/d/prisma-schema

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

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

model Nonprofit {
  id Int @id @default(autoincrement())
  createdAt DateTime @default(now())
  email String @unique
  name String?
}

Create src/libs/

After editing, you can run migration by:

nx run model:migrate-up

Prisma Service in NestJS

Generate the PrismaService:

nx generate @nrwl/nest:service --name=prisma --project=model --directory=lib

Code for libs/model/src/lib/prisma/prisma.service.ts:

import { Injectable, OnModuleDestroy, OnModuleInit } from '@nestjs/common';
import { PrismaClient } from '@prisma/client';

/**
 * https://docs.nestjs.com/recipes/prisma
 */
@Injectable()
export class PrismaService extends PrismaClient implements OnModuleInit, OnModuleDestroy {
  async onModuleInit() {
    await this.$connect();
  }

  async onModuleDestroy() {
    await this.$disconnect();
  }
}

Generate NestJS Resource with GraphQL Code First

yarn add @nestjs/graphql graphql-tools graphql apollo-server-express

In file app/app.module.ts, add the following inside “imports“:

    GraphQLModule.forRoot({
      installSubscriptionHandlers: false,
      // See: https://stackoverflow.com/a/61048144/122441
      autoSchemaFile: process.env.NODE_ENV === 'development' ? 'apps/fund/schema.gql' : true,
    }),

Now you can generate a skeleton resource: (Important: Make sure the name is plural, as it needs that to differentiate between collection and single document queries)

nx generate @nestjs/schematics:resource --name=Nonprofits --sourceRoot=apps/fund/src --type=graphql-code-first

Edit src/app/nonprofits/nonprofits.service.ts, first you must inject PrismaService:

  constructor(private prismaService: PrismaService) {
  }

After that you can use the Prisma client, for example:

import { Nonprofit } from './entities/nonprofit.entity';

// ...

  async findAll(): Promise<Nonprofit[]> {
    const docs = await this.prismaService.nonprofit.findMany();
    console.debug('NonprofitsService.findAll:', docs);
    return docs;
  }

Make sure that you have proper fields in GraphQL entities. For example in src/app/nonprofits/entities/nonprofit.entity.ts:

import { ObjectType, Field, Int, ID, GraphQLISODateTime } from '@nestjs/graphql';

@ObjectType()
export class Nonprofit {
  @Field(() => ID, { description: 'ID' })
  id: number;
  @Field(() => GraphQLISODateTime, { description: 'Created at' })
  createdAt: Date;
  @Field(() => String, { description: 'Email' })
  email: string;
  @Field(() => String, { description: 'Name' })
  name: string;
}

Executing GraphQL Queries

To use it, open GraphQL Playground at http://localhost:3333/graphql

Then you can do a query such as:

{
  nonprofits {
    id, createdAt, email, name
  }
}

To manipulate database contents, you can use your favorite MySQL Client (like MySQL Workbench, etc.). You can also use Prisma Studio by running yarn nx model:studio or:

cd libs/model
../../node_modules/.bin/prisma studio

Auto-Generate GraphQL Resolver for CRUD Queries and Mutations

After using Prisma for some time (I have ever used TypeORM before, and also Mongoose and Typegoose), there are things that I like:

prisma migrate
prisma studio
the generated client typings/code completion is really good (see below)

However, compared to TypeORM in NestJS:

we still need to create entity/input/output classes with GraphQL decorators
Autogenerate GraphQL CRUD: With TypeORM there’s @nestjsx/crud (that is unfortunately seems slow development). With Prisma and Apollo-Server there is Nexus, however there’s no “official” way to integrate with NestJS yet -> discussion here: https://github.com/graphql-nexus/nexus/issues/386

Engineering