Database Seeding

Generate hundreds of related database records for development and testing with proper foreign key relationships.

The Problem

Creating seed data for development requires:

• Manual work — Writing hundreds of INSERT statements
• Relationships — Maintaining foreign key consistency
• Realistic data — Making it look like real production data
• Variety — Different values, not just copy-paste

The JSSON Solution

JSSON

users [
template { id, role }

map (u) = {
  id = u.id
  uuid = "usr-" + u.id + "-" + (u.id * 1234)
  email = "user" + u.id + "@example.com"
  username = "user_" + u.id
  role = u.role

  // Profile
  firstName = u.role == "admin" ? "Admin" : "User"
  lastName = "Number" + u.id
  avatar = "https://api.dicebear.com/7.x/avataaars/svg?seed=" + u.id

  // Settings
  language = u.id % 3 == 0 ? "pt" : (u.id % 3 == 1 ? "en" : "es")
  theme = u.id % 2 == 0 ? "dark" : "light"

  // Status
  isActive = true
  isVerified = u.id <= 50 ? true : false
}

// Admin users
1..5, "admin"

// Regular users
6..100, "user"
]

JSON Output

{
"users": [
  {
    "id": 1,
    "uuid": "usr-1-1234",
    "email": "user1@example.com",
    "username": "user_1",
    "role": "admin",
    "firstName": "Admin",
    "lastName": "Number1",
    "avatar": "https://api.dicebear.com/7.x/avataaars/svg?seed=1",
    "language": "en",
    "theme": "light",
    "isActive": true,
    "isVerified": true
  }
  // ... 99 more users
]
}

Products with Categories

products [
template { id, category }

map (p) = {
  id = p.id
  sku = "PRD-" + p.category + "-" + p.id
  name = p.category + " Product " + p.id
  category = p.category

  // Pricing
  price = (p.id * 10) + 99
  currency = "BRL"
  discount = p.id % 5 == 0 ? 10 : 0

  // Inventory
  stock = p.id * 10
  inStock = true

  // SEO
  slug = p.category + "-product-" + p.id
}

1..30, "electronics"
31..60, "clothing"
61..80, "books"
81..100, "home"
]

Orders with Relationships

orders [
template { id, userId, productId }

map (o) = {
  id = o.id
  orderNumber = "ORD-2025-" + o.id

  // Foreign keys
  userId = o.userId
  productId = o.productId

  // Order details
  quantity = (o.id % 5) + 1
  subtotal = ((o.productId * 10) + 99) * ((o.id % 5) + 1)

  // Status
  status = o.id % 4 == 0 ? "delivered" : (o.id % 4 == 1 ? "shipped" : "pending")
  paymentMethod = o.id % 2 == 0 ? "credit_card" : "pix"
}

// Generate 100 orders
1..25, 1, 1
26..50, 2, 5
51..75, 3, 10
76..100, 4, 15
]

Key Features

Ranges for Scale

// Generate 100 users
1..100, "user"

// Generate 100 products across categories
1..30, "electronics"
31..60, "clothing"

Foreign Keys

// Orders reference users and products
userId = o.userId
productId = o.productId

Variety with Modulo

// Different languages
language = u.id % 3 == 0 ? "pt" : (u.id % 3 == 1 ? "en" : "es")

// Different payment methods
paymentMethod = o.id % 2 == 0 ? "credit_card" : "pix"

Benefits

Realistic — Varied, production-like data
Relationships — Proper foreign keys
Scalable — Generate thousands of records
Consistent — Templates ensure structure
Fast — 100 lines → 200+ records

When to Use

Perfect for:

• Development database seeding
• Testing with realistic data
• Demo environments
• Load testing data

Not ideal for:

• Production data
• Extremely unique records
• Complex business logic

Try It!

1. Save to database-seed.jsson
2. Run: jsson -i database-seed.jsson
3. Import into your database!

What’s Next?

• Geographic Data — Millions of coordinates
• Overview — All examples

Seed your database with ease! 💾