How to create prisma schema for user,cart and order models

To model a User with Orders and Carts in Prisma, you would typically use relational fields to link these models together. Here's a step-by-step guide to creating the schema for this relationship:

Step 1: Define the Schema

In your Prisma schema, define the User, Order, and Cart models, and establish the relationships between them.

// schema.prisma
model User {
  id        Int      @id @default(autoincrement())
  name      String
  email     String   @unique
  orders    Order[]  // One-to-many relation with Order
  carts     Cart[]   // One-to-many relation with Cart
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt
}

model Order {
  id        Int      @id @default(autoincrement())
  userId    Int      // Foreign key to User
  user      User     @relation(fields: [userId], references: [id])
  items     Json     // Assuming Order contains a JSON field for items
  total     Float
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt
}

model Cart {
  id        Int      @id @default(autoincrement())
  userId    Int      // Foreign key to User
  user      User     @relation(fields: [userId], references: [id])
  items     Json     // Assuming Cart contains a JSON field for items
  total     Float
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt
}

Step 2: Run Migrations

After defining your schema, you need to run the migrations to update your database:

npx prisma migrate dev --name add_user_orders_carts

Step 3: Using the Relationships in Code

You can now interact with the User, Order, and Cart models in your application code.

3.1. Creating a User with Orders and Carts

Here's how you can create a user and add orders and carts:

import { PrismaClient } from '@prisma/client';

const prisma = new PrismaClient();

async function main() {
  const user = await prisma.user.create({
    data: {
      name: 'John Doe',
      email: '[email protected]',
      orders: {
        create: [
          {
            items: [
              { name: 'Item 1', price: 100, quantity: 2 },
              { name: 'Item 2', price: 200, quantity: 1 }
            ],
            total: 400,
          }
        ]
      },
      carts: {
        create: [
          {
            items: [
              { name: 'Item A', price: 50, quantity: 3 },
              { name: 'Item B', price: 150, quantity: 1 }
            ],
            total: 300,
          }
        ]
      }
    }
  });

  console.log(user);
}

main()
  .catch(e => {
    throw e;
  })
  .finally(async () => {
    await prisma.$disconnect();
  });

3.2. Querying a User with Orders and Carts

You can also query a user and include their orders and carts:

import { PrismaClient } from '@prisma/client';

const prisma = new PrismaClient();

async function main() {
  const user = await prisma.user.findUnique({
    where: { email: '[email protected]' },
    include: {
      orders: true,
      carts: true
    }
  });

  console.log(user);
}

main()
  .catch(e => {
    throw e;
  })
  .finally(async () => {
    await prisma.$disconnect();
  });

3.3. Updating Orders and Carts

To update an order or cart, you can use the following code:

import { PrismaClient } from '@prisma/client';

const prisma = new PrismaClient();

async function main() {
  const updatedOrder = await prisma.order.update({
    where: { id: 1 },
    data: {
      items: [
        { name: 'Item 1 Updated', price: 120, quantity: 2 },
        { name: 'Item 2 Updated', price: 220, quantity: 1 }
      ],
      total: 460,
    }
  });

  const updatedCart = await prisma.cart.update({
    where: { id: 1 },
    data: {
      items: [
        { name: 'Item A Updated', price: 55, quantity: 3 },
        { name: 'Item B Updated', price: 160, quantity: 1 }
      ],
      total: 325,
    }
  });

  console.log(updatedOrder);
  console.log(updatedCart);
}

main()
  .catch(e => {
    throw e;
  })
  .finally(async () => {
    await prisma.$disconnect();
  });