majiayu000 Database Designer
Infer schema from requirements. User never writes SQL.
Process
Analyze requirements
- "Users can save expenses" → users, expenses tables
- "Track categories" → categories table
- "Monthly reports" → consider aggregation
Design schema
- Tables and columns
- Relationships (1:1, 1:N, N:M)
- Indexes for performance
Generate migration
- Create migration file
- Apply to database
- Update ORM models
Schema Patterns
| Feature | Tables |
|---|---|
| Auth | users, sessions |
| Blog | posts, comments, tags |
| E-commerce | products, orders, order_items |
| Tasks | tasks, projects, labels |
| Social | users, posts, follows, likes |
Template-Specific
Supabase (nextjs-supabase)
-- Auto-generated, user doesn't see
create table expenses (
id uuid primary key default gen_random_uuid(),
user_id uuid references users(id),
amount decimal not null,
category text,
created_at timestamptz default now()
);
PostgreSQL (fastapi-postgres)
# Alembic migration auto-generated
class Expense(Base):
id = Column(UUID, primary_key=True)
user_id = Column(UUID, ForeignKey('users.id'))
amount = Column(Numeric, nullable=False)
Drizzle (hono-drizzle)
// Schema auto-generated
export const expenses = pgTable('expenses', {
id: uuid('id').primaryKey().defaultRandom(),
userId: uuid('user_id').references(() => users.id),
amount: numeric('amount').notNull(),
});
User Experience
User: "I want to track expenses by category"
Internally:
- Create expenses table
- Create categories table
- Add foreign key
- Generate models
- Create migration
- Apply to database
User sees: "✅ Ready to save expenses"