How to get enums in prisma client?

When using the Prisma Client, retrieving enum values typically involves several steps to ensure correct retrieval and usage of these enum values from the model. The following is a structured approach to handle this issue:

Step 1: Define the Model and Include Enum Type

First, define the enum type in your Prisma model. Suppose we have a User model that includes an enum type named Role, defined as:

prisma
// schema.prisma

enum Role {
  ADMIN
  USER
  GUEST
}

model User {
  id    Int    @id @default(autoincrement())
  name  String
  role  Role
}

Step 2: Migrate the Database

Ensure your database is up-to-date and includes the enum definition. You can migrate the database by running the following command:

bash
npx prisma migrate dev --name init

Step 3: Use the Prisma Client to Query Enum Values

In your application code, you can use the Prisma Client to query data containing enum values. For example, if you want to retrieve all users and their roles, you can do the following:

javascript
const { PrismaClient } = require('@prisma/client');
const prisma = new PrismaClient();

async function main() {
  const users = await prisma.user.findMany({
    select: {
      name: true,
      role: true,
    },
  });
  console.log(users);
}

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

This code outputs the names and roles of all users, with the role being an enum type.

Step 4: Handle Enum Values

In your application logic, you may need to make decisions based on enum values. For example:

javascript
users.forEach(user => {
  if (user.role === 'ADMIN') {
    console.log(`${user.name} is an admin.`);
  } else {
    console.log(`${user.name} is not an admin.`);
  }
});

This enables you to execute different logic based on the user's role.

Summary

By following these steps, you can effectively retrieve and use enum types in the Prisma Client. This not only helps maintain data consistency at the database level but also allows you to conveniently use these enum values to control the flow in application logic.