seed-generator

Seed Generator

Analyze database schema and generate realistic test data. Write seed files directly.

Process

1. Analyze Schema - Read database models/schema
2. Understand Relations - Map foreign keys and constraints
3. Generate Data - Create realistic fake data
4. Write Seeds - Create seed script files
5. Test - Run seeds to verify

Schema Analysis

# Find Prisma schema
cat prisma/schema.prisma 2>/dev/null | head -100

# Find Drizzle schema
find src -name "schema.ts" -path "*/db/*" | xargs cat 2>/dev/null

# Find TypeORM entities
find src -name "*.entity.ts" | xargs cat 2>/dev/null | head -100

# Find existing seeds
find . -name "seed*.ts" -o -name "seed*.js" 2>/dev/null

Data Generation Patterns

Users

const users = [
  {
    id: 'user_1',
    email: '[email protected]',
    name: 'Admin User',
    role: 'ADMIN',
    createdAt: new Date('2024-01-01'),
  },
  {
    id: 'user_2',
    email: '[email protected]',
    name: 'John Doe',
    role: 'USER',
    createdAt: new Date('2024-01-15'),
  },
  // Generate more with faker
];

Products

const products = [
  {
    id: 'prod_1',
    name: 'Premium Widget',
    price: 2999, // cents
    description: 'A high-quality widget for professionals',
    category: 'ELECTRONICS',
    stock: 100,
    createdAt: new Date('2024-01-01'),
  },
];

Orders (with relations)

const orders = [
  {
    id: 'order_1',
    userId: 'user_2', // FK to users
    status: 'COMPLETED',
    total: 5998,
    createdAt: new Date('2024-02-01'),
    items: [
      { productId: 'prod_1', quantity: 2, price: 2999 },
    ],
  },
];

Seed Script Template

Prisma Seed

// prisma/seed.ts
import { PrismaClient } from '@prisma/client';

const prisma = new PrismaClient();

async function main() {
  console.log('Seeding database...');

  // Clear existing data (in correct order for FKs)
  await prisma.orderItem.deleteMany();
  await prisma.order.deleteMany();
  await prisma.product.deleteMany();
  await prisma.user.deleteMany();

  // Create users
  const admin = await prisma.user.create({
    data: {
      email: '[email protected]',
      name: 'Admin User',
      role: 'ADMIN',
    },
  });

  const user = await prisma.user.create({
    data: {
      email: '[email protected]',
      name: 'John Doe',
      role: 'USER',
    },
  });

  // Create products
  const products = await prisma.product.createMany({
    data: [
      { name: 'Widget A', price: 1999, stock: 50 },
      { name: 'Widget B', price: 2999, stock: 30 },
      { name: 'Widget C', price: 4999, stock: 20 },
    ],
  });

  // Create orders with items
  const order = await prisma.order.create({
    data: {
      userId: user.id,
      status: 'COMPLETED',
      total: 4998,
      items: {
        create: [
          { productId: products[0].id, quantity: 1, price: 1999 },
          { productId: products[1].id, quantity: 1, price: 2999 },
        ],
      },
    },
  });

  console.log('Seeding complete!');
  console.log({ users: 2, products: 3, orders: 1 });
}

main()
  .catch((e) => {
    console.error(e);
    process.exit(1);
  })
  .finally(async () => {
    await prisma.$disconnect();
  });