drizzle

# Drizzle ORM Schema Style Guide

## Configuration

- Config: `drizzle.config.ts`
- Schemas: `src/database/schemas/`
- Migrations: `src/database/migrations/`
- Dialect: `postgresql` with `strict: true`

## Helper Functions

Location: `src/database/schemas/_helpers.ts`

- `timestamptz(name)`: Timestamp with timezone
- `createdAt()`, `updatedAt()`, `accessedAt()`: Standard timestamp columns
- `timestamps`: Object with all three for easy spread

## Naming Conventions

- **Tables**: Plural snake_case (`users`, `session_groups`)
- **Columns**: snake_case (`user_id`, `created_at`)

## Column Definitions

### Primary Keys

```typescript
id: text('id')
  .primaryKey()
  .$defaultFn(() => idGenerator('agents'))
  .notNull(),
```

ID prefixes make entity types distinguishable. For internal tables, use `uuid`.

### Foreign Keys

```typescript
userId: text('user_id')
  .references(() => users.id, { onDelete: 'cascade' })
  .notNull(),
```

### Timestamps

```typescript
...timestamps,  // Spread from _helpers.ts
```

### Indexes

```typescript
// Return array (object style deprecated)
(t) => [uniqueIndex('client_id_user_id_unique').on(t.clientId, t.userId)],
```

## Type Inference

```typescript
export const insertAgentSchema = createInsertSchema(agents);
export type NewAgent = typeof agents.$inferInsert;
export type AgentItem = typeof agents.$inferSelect;
```

## Example Pattern

```typescript
export const agents = pgTable(
  'agents',
  {
    id: text('id').primaryKey().$defaultFn(() => idGenerator('agents')).notNull(),
    slug: varchar('slug', { length: 100 }).$defaultFn(() => randomSlug(4)).unique(),
    userId: text('user_id').references(() => users.id, { onDelete: 'cascade' }).notNull(),
    clientId: text('client_id'),
    chatConfig: jsonb('chat_config').$type<LobeAgentChatConfig>(),
    ...timestamps,
  },
  (t) => [uniqueIndex('client_id_user_id_unique').on(t.clientId, t.userId)],
);
```

## Common Patterns

### Junction Tables (Many-to-Many)

```typescript
export con