db-seed

Name: db-seed
Author: jezweb

841installs96forks

How to install db-seed?

jezweb/claude-skills/db-seed

$npx -y skills add jezweb/claude-skills --skill db-seed

Installs into the current project.

Summary

Generate database seed scripts with realistic sample data. Reads Drizzle schemas or SQL migrations, respects foreign key ordering, produces idempotent TypeScript or SQL seed files. Handles D1 batch limits, unique constraints, and domain-appropriate data. Use when populating dev/d

Files · 1

View on GitHub

SKILL.md

1	# Database Seed Generator
2
3	Generate seed scripts that populate databases with realistic, domain-appropriate sample data. Reads your schema and produces ready-to-run seed files.
4
5	## Workflow
6
7	### 1. Find the Schema
8
9	Scan the project for schema definitions:
10
11	\| Source \| Location pattern \|
12	\|--------\|-----------------\|
13	\| Drizzle schema \| `src/db/schema.ts`, `src/schema/*.ts`, `db/schema.ts` \|
14	\| D1 migrations \| `drizzle/.sql`, `migrations/.sql` \|
15	\| Raw SQL \| `schema.sql`, `db/*.sql` \|
16	\| Prisma \| `prisma/schema.prisma` \|
17
18	Read all schema files. Build a mental model of:
19	- Tables and their columns
20	- Data types and constraints (NOT NULL, UNIQUE, DEFAULT)
21	- Foreign key relationships (which tables reference which)
22	- JSON fields stored as TEXT (common in D1/SQLite)
23
24	### 2. Determine Seed Parameters
25
26	Ask the user:
27
28	\| Parameter \| Options \| Default \|
29	\|-----------\|---------\|---------\|
30	\| Purpose \| dev, demo, testing \| dev \|
31	\| Volume \| small (5-10 rows/table), medium (20-50), large (100+) \| small \|
32	\| Domain context \| "e-commerce store", "SaaS app", "blog", etc. \| Infer from schema \|
33	\| Output format \| TypeScript (Drizzle), raw SQL, or both \| Match project's ORM \|
34
35	Purpose affects data quality:
36	- dev: Varied data, some edge cases (empty fields, long strings, unicode)
37	- demo: Polished data that looks good in screenshots and presentations
38	- testing: Systematic data covering boundary conditions, duplicates, special characters
39
40	### 3. Plan Insert Order
41
42	Build a dependency graph from foreign keys. Insert parent tables before children.
43
44	Example order for a blog schema:
45	```
46	1. users (no dependencies)
47	2. categories (no dependencies)
48	3. posts (depends on users, categories)
49	4. comments (depends on users, posts)
50	5. tags (no dependencies)
51	6. post_tags (depends on posts, tags)
52	```
53
54	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).
55
56	### 4. Generate Realistic Data
57
58	Do NOT use generic placeholders like "test123", "foo@bar.com", or "Lorem ipsum". Generate data that matches the domain.
59
60	#### Data Generation Patterns (no external libraries needed)
61
62	Names: Use a hardcoded list of common names. Mix genders and cultural backgrounds.
63	```typescript
64	const firstNames = ['Sarah', 'James', 'Priya', 'Mohammed', 'Emma', 'Wei', 'Carlos', 'Aisha'];
65	const lastNames = ['Chen', 'Smith', 'Patel', 'Garcia', 'Kim', 'O\'Brien', 'Nguyen', 'Wilson'];
66	```
67
68	Emails: Derive from names — `sarah.chen@example.com`. Use `example.com` domain (RFC 2606 reserved).
69
70	Dates: Generate within a realistic range. Use ISO 8601 format for D1/SQLite.
71	```typescript
72	const randomDate = (daysBack: number) => {
73	const d = new Date();
74	d.setDate(d.getDate() - Math.floor(Math.random() * daysBack));
75	return d.toISOString();
76	};
77	```
78
79	IDs: Use `crypto.randomUUID()` for UUIDs, or sequential integers if the schema uses auto-increment.
80
81	Deterministic seeding: For reproducible data, use a seeded PRNG:
82	```typescript
83	function seededRandom(seed: number) {
84	return () => {
85	seed = (seed * 16807) % 2147483647;
86	return (seed - 1) / 2147483646;
87	};
88	}
89	const rand = seededRandom(42); // Same seed = same data every time
90	```
91
92	Prices/amounts: Use realistic ranges. `(rand() * 900 + 100).toFixed(2)` for $1-$10 range.
93
94	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.
95
96	### 5. Output Format
97
98	#### TypeScript (Drizzle ORM)
99
100	```typescript
101	// scripts/seed.ts
102	import { drizzle } from 'drizzle-orm/d1';
103	import * as schema from '../src/db/schema';
104
105	export async function seed(db: ReturnType<typeof drizzle>) {
106	console.log('Seeding database...');
107
108	// Clear existing data (reverse dependency order)
109	await db.delete(schema.comments);
110	await db.delete(schema.posts);
111	await db.delete(schema.users);
112
113	// Insert users
114	const users = [
115	{ id: crypto.randomUUID(), name: 'Sarah Chen', email: 'sarah@example.com', ... },
116	// ...
117	];
118
119	// D1 batch limit: 10 rows per INSERT
120	for (let i = 0; i < users.length; i += 10) {
121	await db.insert(schema.users).values(users.slice(i, i + 10));
122	}
123
124	// Insert posts (references users)
125	const posts = [
126	{ id: crypto.randomUUID(), userId: users[0].id, title: '...', ... },
127	// ...
128	];
129
130	for (let i = 0; i < posts.length; i

People who liked this also viewed

6 picks

Type

db-seed

841installs96forks

View on GitHub

How to install db-seed?

jezweb/claude-skills/db-seed

$npx -y skills add jezweb/claude-skills --skill db-seed

Installs into the current project.

Summary

Files · 1

View on GitHub

SKILL.md

1	# Database Seed Generator
2
3	Generate seed scripts that populate databases with realistic, domain-appropriate sample data. Reads your schema and produces ready-to-run seed files.
4
5	## Workflow
6
7	### 1. Find the Schema
8
9	Scan the project for schema definitions:
10
11	\| Source \| Location pattern \|
12	\|--------\|-----------------\|
13	\| Drizzle schema \| `src/db/schema.ts`, `src/schema/*.ts`, `db/schema.ts` \|
14	\| D1 migrations \| `drizzle/.sql`, `migrations/.sql` \|
15	\| Raw SQL \| `schema.sql`, `db/*.sql` \|
16	\| Prisma \| `prisma/schema.prisma` \|
17
18	Read all schema files. Build a mental model of:
19	- Tables and their columns
20	- Data types and constraints (NOT NULL, UNIQUE, DEFAULT)
21	- Foreign key relationships (which tables reference which)
22	- JSON fields stored as TEXT (common in D1/SQLite)
23
24	### 2. Determine Seed Parameters
25
26	Ask the user:
27
28	\| Parameter \| Options \| Default \|
29	\|-----------\|---------\|---------\|
30	\| Purpose \| dev, demo, testing \| dev \|
31	\| Volume \| small (5-10 rows/table), medium (20-50), large (100+) \| small \|
32	\| Domain context \| "e-commerce store", "SaaS app", "blog", etc. \| Infer from schema \|
33	\| Output format \| TypeScript (Drizzle), raw SQL, or both \| Match project's ORM \|
34
35	Purpose affects data quality:
36	- dev: Varied data, some edge cases (empty fields, long strings, unicode)
37	- demo: Polished data that looks good in screenshots and presentations
38	- testing: Systematic data covering boundary conditions, duplicates, special characters
39
40	### 3. Plan Insert Order
41
42	Build a dependency graph from foreign keys. Insert parent tables before children.
43
44	Example order for a blog schema:
45	```
46	1. users (no dependencies)
47	2. categories (no dependencies)
48	3. posts (depends on users, categories)
49	4. comments (depends on users, posts)
50	5. tags (no dependencies)
51	6. post_tags (depends on posts, tags)
52	```
53
54	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).
55
56	### 4. Generate Realistic Data
57
58	Do NOT use generic placeholders like "test123", "foo@bar.com", or "Lorem ipsum". Generate data that matches the domain.
59
60	#### Data Generation Patterns (no external libraries needed)
61
62	Names: Use a hardcoded list of common names. Mix genders and cultural backgrounds.
63	```typescript
64	const firstNames = ['Sarah', 'James', 'Priya', 'Mohammed', 'Emma', 'Wei', 'Carlos', 'Aisha'];
65	const lastNames = ['Chen', 'Smith', 'Patel', 'Garcia', 'Kim', 'O\'Brien', 'Nguyen', 'Wilson'];
66	```
67
68	Emails: Derive from names — `sarah.chen@example.com`. Use `example.com` domain (RFC 2606 reserved).
69
70	Dates: Generate within a realistic range. Use ISO 8601 format for D1/SQLite.
71	```typescript
72	const randomDate = (daysBack: number) => {
73	const d = new Date();
74	d.setDate(d.getDate() - Math.floor(Math.random() * daysBack));
75	return d.toISOString();
76	};
77	```
78
79	IDs: Use `crypto.randomUUID()` for UUIDs, or sequential integers if the schema uses auto-increment.
80
81	Deterministic seeding: For reproducible data, use a seeded PRNG:
82	```typescript
83	function seededRandom(seed: number) {
84	return () => {
85	seed = (seed * 16807) % 2147483647;
86	return (seed - 1) / 2147483646;
87	};
88	}
89	const rand = seededRandom(42); // Same seed = same data every time
90	```
91
92	Prices/amounts: Use realistic ranges. `(rand() * 900 + 100).toFixed(2)` for $1-$10 range.
93
94	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.
95
96	### 5. Output Format
97
98	#### TypeScript (Drizzle ORM)
99
100	```typescript
101	// scripts/seed.ts
102	import { drizzle } from 'drizzle-orm/d1';
103	import * as schema from '../src/db/schema';
104
105	export async function seed(db: ReturnType<typeof drizzle>) {
106	console.log('Seeding database...');
107
108	// Clear existing data (reverse dependency order)
109	await db.delete(schema.comments);
110	await db.delete(schema.posts);
111	await db.delete(schema.users);
112
113	// Insert users
114	const users = [
115	{ id: crypto.randomUUID(), name: 'Sarah Chen', email: 'sarah@example.com', ... },
116	// ...
117	];
118
119	// D1 batch limit: 10 rows per INSERT
120	for (let i = 0; i < users.length; i += 10) {
121	await db.insert(schema.users).values(users.slice(i, i + 10));
122	}
123
124	// Insert posts (references users)
125	const posts = [
126	{ id: crypto.randomUUID(), userId: users[0].id, title: '...', ... },
127	// ...
128	];
129
130	for (let i = 0; i < posts.length; i

People who liked this also viewed

6 picks

Type