/datamodellm

name: datamodellm
description: Create visual data models for database schemas using Nimbalyst's DataModelLM editor. Use when the user wants to design a data model, database schema, entity relationship diagram, or Prisma schema.

DataModelLM - Visual Data Modeling

DataModelLM is Nimbalyst's visual editor for creating database schemas using Prisma format. It displays entity-relationship diagrams with a visual canvas.

When to Use DataModelLM

• Designing database schemas
• Creating entity relationship diagrams (ERDs)
• Planning data models for applications
• Working with Prisma schemas
• Any visual data modeling task

File Format

• **Extension**: `.prisma`
• **Format**: Prisma schema with special metadata header
• **Location**: Any directory (commonly workspace root or `models/`, `schema/`)

Required Header

Every DataModelLM file MUST start with a `@nimbalyst` metadata comment:

// @nimbalyst {"viewport":{"x":0,"y":0,"zoom":1},"positions":{},"entityViewMode":"standard"}

Basic Structure

// @nimbalyst {"viewport":{"x":0,"y":0,"zoom":1},"positions":{},"entityViewMode":"standard"}

datasource db {
  provider = "postgresql"
  url      = env("DATABASE_URL")
}

model User {
  id        Int      @id @default(autoincrement())
  email     String   @unique
  name      String?
  posts     Post[]
  createdAt DateTime @default(now())
  updatedAt DateTime @updatedAt
}

model Post {
  id        Int      @id @default(autoincrement())
  title     String
  content   String?
  published Boolean  @default(false)
  author    User     @relation(fields: [authorId], references: [id])
  authorId  Int
  createdAt DateTime @default(now())
}

Supported Types

Scalar Types

• `Int`, `BigInt`, `Float`, `Decimal`
• `String`, `Boolean`
• `DateTime`, `Json`, `Bytes`

Modifiers

• `?` - Optional field
• `[]` - Array/list

Attributes

• `@id` - Primary key
• `@unique` - Unique constraint
• `@default(value)` - Default value
• `@updatedAt` - Auto-update timestamp
• `@relation` - Define relationships

Relationship Patterns

One-to-Many

model User {
  posts Post[]
}
model Post {
  author   User @relation(fields: [authorId], references: [id])
  authorId Int
}

One-to-One

model User {
  profile Profile?
}
model Profile {
  user   User @relation(fields: [userId], references: [id])
  userId Int  @unique
}

Many-to-Many (Implicit)

model Post {
  categories Category[]
}
model Category {
  posts Post[]
}

Best Practices

1. **Always include the @nimbalyst header** - Required for visual editor 2. **Use meaningful model names** - PascalCase, singular (User not Users) 3. **Include timestamps** - Add createdAt and updatedAt to most models 4. **Define explicit relations** - Always specify @relation with fields and references