This tutorial is for how to integrate Dirzzle orm with Nest js. The example uses postgres as connection database

Add Database url to env file -

# DATABASE_URL='postgresql://<host>:<password>@localhost:5432/<database>'

If you encounter some problems regarding connecting to database use these -

# DATABASE_URL='postgresql://<host>:<password>@localhost:5432/<database>?sslmode=require&connect_timeout=10&pool_timeout=15

Create drizzle.config.ts file inside root folder

import { defineConfig } from 'drizzle-kit';
export default defineConfig({
  dialect: 'postgresql',
  schema: './src/schema.ts',
  out: './drizzle',
  dbCredentials: {
    url: process.env.DATABASE_URL,
  },
});

Create schema file inside root directory -

//schema.ts
import {
  pgTable,
  pgEnum,
  serial,
  timestamp,
  text,
  integer,
  primaryKey,
  boolean,
  uuid,
} from 'drizzle-orm/pg-core';
import { InferSelectModel } from 'drizzle-orm';

export const posts = pgTable('posts', {
  id: serial('id').primaryKey(),
  authorId: integer('author_id')
    .notNull()
    .references(() => users.id, {
      onDelete: 'cascade',
      onUpdate: 'no action',
    }),
  content: text('content'),
  mediaUrl: text('media_url'),
  createdAt: timestamp('created_at').notNull().defaultNow(),
  updatedAt: timestamp('updated_at').notNull().defaultNow(),
});

Create a drizzle.provider.ts file inside drizzle repository folder-

//drizzle.provider.ts
import { drizzle } from 'drizzle-orm/node-postgres';
import { Pool } from 'pg';
import * as schema from '../../schema';
import { ConfigService } from '@nestjs/config';
import { NodePgDatabase } from 'drizzle-orm/node-postgres';

export const DrizzleAsyncProvider = 'DrizzleAsyncProvider';

export const drizzleProvider = [
  {
    provide: DrizzleAsyncProvider,
    inject: [ConfigService],
    useFactory: async (configService: ConfigService) => {
      const connectionString = configService.get<string>('DATABASE_URL');
      const pool = new Pool({
        connectionString,
      });

      return drizzle(pool, { schema }) as NodePgDatabase<typeof schema>;
    },
  },
];

//drizzle.module.ts
import { Module } from '@nestjs/common';
import { DrizzleAsyncProvider, drizzleProvider } from './drizzle.provider';

@Module({
  providers: [...drizzleProvider],
  exports: [DrizzleAsyncProvider],
})
export class DrizzleModule {}

How to use it ?

//post.service.ts
import { Injectable, NotFoundException } from '@nestjs/common';
import { Inject } from '@nestjs/common';
import { NodePgDatabase } from 'drizzle-orm/node-postgres';
import * as sc from '../../schema';
import { DrizzleAsyncProvider } from 'src/core-modules/drizzle/drizzle.provider';
import * as q from 'drizzle-orm';

@Injectable()
export class PostService {
  constructor(
    @Inject(DrizzleAsyncProvider)
    private db: NodePgDatabase<typeof sc>,
    private cloudinaryService: CloudinaryService,
  ) {}

 async createPost(userId: number, createPostDto: CreatePostDto) {
    const [post] = await this.db
      .insert(sc.posts)
      .values({ authorId: userId, ...createPostDto })
      .returning();
    const [newpost] = await this.selectPostsWithAuthor(userId).where(
      q.eq(sc.posts.id, post.id),
    );
    return newpost;
  }

Inside package.json add

"scripts": {
    "generate": "drizzle-kit generate",
    "migrate": "drizzle-kit migrate",
    "studio": "drizzle-kit studio"
  },

Generate - create migration folder containing SQL code for the schema file you created

Migrate - apply those migrations

Studio - connect with the drizzle studio

Now run

npm run generate

Then,

npm run migrate

How to integrate Drizzle ORM with Nest Js