Database Seeding

Flash ORM includes a powerful seeding system that automatically generates realistic test data for your database tables.

Quick Start

# Seed all tables with default count (10 rows each)
flash seed

# Seed with custom row count
flash seed --count 100

# Seed specific table
flash seed --table users --count 50

# Seed multiple tables with different counts
flash seed users:100 posts:500 comments:1000

# Truncate before seeding (fresh start)
flash seed --truncate

# Skip confirmation prompts
flash seed --truncate --force

Features

Smart Data Generation

FlashORM automatically generates appropriate data based on column names and types:

Column Pattern	Generated Data
email	realistic emails (john.doe@example.com)
name, first_name, last_name	human names
phone	phone numbers
url, website	URLs
address, city, country	location data
created_at, updated_at	timestamps
password	hashed passwords
uuid, id	UUIDs or auto-increment
price, amount	currency values
description, bio	lorem ipsum text

Foreign Key Support

FlashORM automatically handles relationships:

-- Given this schema:
CREATE TABLE users (
  id SERIAL PRIMARY KEY,
  name VARCHAR(100)
);

CREATE TABLE posts (
  id SERIAL PRIMARY KEY,
  user_id INTEGER REFERENCES users(id),
  title VARCHAR(200)
);

When you run flash seed:

1. Seeds users table first
2. Uses existing user IDs when seeding posts
3. Maintains referential integrity

Dependency Graph

FlashORM builds a dependency graph to determine the correct seeding order:

seeding order:
  1. users (no dependencies)
  2. categories (no dependencies)
  3. posts (depends on users)
  4. comments (depends on users, posts)

Command Options

flash seed [tables...] [flags]

Positional Arguments

You can specify tables with custom counts using the table:count syntax:

# Seed users with 100 rows, posts with 500, comments with 1000
flash seed users:100 posts:500 comments:1000

This is useful when you need different amounts of data for different tables.

Flags

Flag	Short	Description	Default
--count	-c	Rows to generate per table	10
--table	-t	Seed specific table only	all
--truncate		Truncate tables before seeding	false
--force	-f	Skip confirmation prompts	false
--relations		Include foreign key relationships	true

Examples

Development Setup

# Fresh database with test data
flash reset --force
flash apply
flash seed --count 50

Seed Specific Tables

# Seed only users table
flash seed --table users --count 100

# Seed with fresh data
flash seed --table posts --truncate --count 200

Multiple Tables with Different Counts

# Realistic data distribution
flash seed users:50 posts:200 comments:1000

# E-commerce example
flash seed categories:10 products:100 orders:500 order_items:2000

# Social media example
flash seed users:100 posts:500 likes:5000 follows:2000

Large Dataset

# Generate large dataset for performance testing
flash seed --count 1000 --force

# Stress test with specific distributions
flash seed users:10000 posts:50000 comments:200000 --force

CI/CD Pipeline

# Automated test setup
flash reset --force && flash apply && flash seed --count 25 --force

Output

🌱 Seeding database...
  Analyzing schema dependencies...
  Seeding order: users → posts → comments

  ✅ users: 50 records inserted
  ✅ posts: 100 records inserted  
  ✅ comments: 200 records inserted

✨ Seeding complete! 350 total records.

Supported Databases

• ✅ PostgreSQL
• ✅ MySQL
• ✅ SQLite

Tips

For Testing

# Reset and seed before each test run
flash reset --force && flash apply && flash seed

For Demo Data

# Create realistic demo environment
flash seed --count 25  # Just enough to look populated

Custom Seed Data

For custom seed data beyond auto-generation, create SQL seed files:

-- db/seeds/admin_users.sql
INSERT INTO users (name, email, role) VALUES
  ('Admin', 'admin@example.com', 'admin'),
  ('Support', 'support@example.com', 'support');

Then run:

flash raw db/seeds/admin_users.sql