- JSON fields stored as TEXT (common in D1/SQLite)
### 2. Determine Seed Parameters
Ask the user:
| Parameter | Options | Default |
|-----------|---------|---------|
| Purpose | dev, demo, testing | dev |
| Volume | small (5-10 rows/table), medium (20-50), large (100+) | small |
| Domain context | "e-commerce store", "SaaS app", "blog", etc. | Infer from schema |
| Output format | TypeScript (Drizzle), raw SQL, or both | Match project's ORM |
**Purpose affects data quality**:
- **dev**: Varied data, some edge cases (empty fields, long strings, unicode)
- **demo**: Polished data that looks good in screenshots and presentations
- **testing**: Systematic data covering boundary conditions, duplicates, special characters
### 3. Plan Insert Order
Build a dependency graph from foreign keys. Insert parent tables before children.
Example order for a blog schema:
```
1. users (no dependencies)
2. categories (no dependencies)
3. posts (depends on users, categories)
4. comments (depends on users, posts)
5. tags (no dependencies)
6. post_tags (depends on posts, tags)
```
**Circular dependencies**: If table A references B and B references A, use nullable foreign keys and insert in two passes (insert with NULL, then UPDATE).
### 4. Generate Realistic Data
**Do NOT use generic placeholders** like "test123", "foo@bar.com", or "Lorem ipsum". Generate data that matches the domain.
#### Data Generation Patterns (no external libraries needed)
**Names**: Use a hardcoded list of common names. Mix genders and cultural backgrounds.
**IDs**: Use `crypto.randomUUID()` for UUIDs, or sequential integers if the schema uses auto-increment.
**Deterministic seeding**: For reproducible data, use a seeded PRNG:
```typescript
function seededRandom(seed: number) {
return () => {
seed = (seed * 16807) % 2147483647;
return (seed - 1) / 2147483646;
};
}
const rand = seededRandom(42); // Same seed = same data every time
```
**Prices/amounts**: Use realistic ranges. `(rand() * 900 + 100).toFixed(2)` for $1-$10 range.
**Descriptions/content**: Write 3-5 realistic variations per content type and cycle through them. Don't generate AI-sounding prose — write like real user data.
### 5. Output Format
#### TypeScript (Drizzle ORM)
```typescript
// scripts/seed.ts
import { drizzle } from 'drizzle-orm/d1';
import * as schema from '../src/db/schema';
export async function seed(db: ReturnType<typeof drizzle>) {
