Convert SQL ENUM and CHECK Constraints to Prisma Enums

SQL Enums to Prisma Enums

Prisma has first-class support for enums via the enum keyword. SQL databases represent enumerations in different ways, and the converter handles each variant.

PostgreSQL CREATE TYPE

CREATE TYPE user_role AS ENUM ('admin', 'editor', 'viewer');
CREATE TYPE post_status AS ENUM ('draft', 'published', 'archived');

CREATE TABLE users (
  id SERIAL PRIMARY KEY,
  name VARCHAR(255) NOT NULL,
  role user_role NOT NULL DEFAULT 'viewer'
);

CREATE TABLE posts (
  id SERIAL PRIMARY KEY,
  title VARCHAR(255) NOT NULL,
  status post_status NOT NULL DEFAULT 'draft',
  author_id INTEGER NOT NULL REFERENCES users(id)
);

Generated Prisma Schema

enum UserRole {
  admin
  editor
  viewer
}

enum PostStatus {
  draft
  published
  archived
}

model User {
  id    Int      @id @default(autoincrement())
  name  String
  role  UserRole @default(admin)
  posts Post[]

  @@map("users")
}

model Post {
  id       Int        @id @default(autoincrement())
  title    String
  status   PostStatus @default(draft)
  authorId Int        @map("author_id")
  author   User       @relation(fields: [authorId], references: [id])

  @@map("posts")
}

MySQL ENUM Column

MySQL defines enums inline:

CREATE TABLE tickets (
  id INT AUTO_INCREMENT PRIMARY KEY,
  priority ENUM('low', 'medium', 'high', 'critical') NOT NULL DEFAULT 'medium'
);

The converter extracts the values and creates a Prisma enum:

enum TicketPriority {
  low
  medium
  high
  critical
}

CHECK Constraint to Enum

CREATE TABLE orders (
  id SERIAL PRIMARY KEY,
  status VARCHAR(20) NOT NULL,
  CONSTRAINT chk_status CHECK (status IN ('pending', 'processing', 'shipped', 'delivered'))
);

The converter parses the CHECK constraint's IN (...) list and generates a Prisma enum.

Enum Naming

SQL name	Prisma enum name
user_role	UserRole (PascalCase)
post_status	PostStatus
Inline MySQL ENUM on priority	TicketPriority ({Model}{Field})

Value Mapping

Prisma enum values must be valid identifiers. If SQL enum values contain special characters or start with numbers, the converter uses @map:

enum HttpMethod {
  GET
  POST
  PUT
  DELETE @map("delete")
}

Migration Considerations

Adding a new value to a Prisma enum generates an ALTER TYPE ... ADD VALUE migration for PostgreSQL. Removing values is not directly supported — you must create a new enum and migrate data. Plan your enums with future extensibility in mind.