How do we solve Prisma N+1 query problems in high-traffic Adidas-scale inventory apps with NestJS?

// BAD: N+1 problem (many queries)
const products = await prisma.product.findMany();
for (const product of products) {
  product.stock = await prisma.stock.findFirst({ where: { productId: product.id } });
}

// GOOD: Single query with relation included
const products = await prisma.product.findMany({
  include: { stock: true }
});

// or with JOIN strategy for single query
const products = await prisma.product.findMany({
  include: { stock: true },
  relationLoadStrategy: 'join'
});