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 const agentsKnowledgeBases = pgTable(
  'agents_knowledge_bases',
  {
    agentId: text('agent_id')
      .references(() => agents.id, { onDelete: 'cascade' })
      .notNull(),
    knowledgeBaseId: text('knowledge_base_id')
      .references(() => knowledgeBases.id, { onDelete: 'cascade' })
      .notNull(),
    userId: text('user_id')
      .references(() => users.id, { onDelete: 'cascade' })
      .notNull(),
    enabled: boolean('enabled').default(true),
    ...timestamps,
  },
  (t) => [primaryKey({ columns: [t.agentId, t.knowledgeBaseId] })],
);
```

## Query Style

**Always use `db.select()` builder API. Never use `db.query.*` relational API** (`findMany`, `findFirst`, `with:`).

The relational API generates complex lateral joins with `json_build_array` that are fragile and hard to debug.

### Select Single Row

```typescript
// ✅ Good
const [result] = await this.db
  .select()
  .from(agents)
  .where(eq(agents.id, id))
  .limit(1);
return result;

// ❌ Bad: relational API
return this.db.query.agents.findFirst({
  where: eq(agents.id, id),
});
```

### Select with JOIN

```typescript
// ✅ Good: explicit select + leftJoin
const rows = await this.db
  .select({
    runId: agentEvalRunTopics.runId,
    score: agentEvalRunTopics.score,
    testCase: agentEvalTestCases,
    topic: topics,
  })
  .from(agentEvalRunTopics)
  .leftJoin(agentEvalTestCases, eq(agentEvalRunTopics.testCaseId, agentEvalTestCases.id))
  .leftJoin(topics, eq(agentEvalRunTopics.topicId, topics.id))
  .where(eq(agentEvalRunTopics.runId, runId))
  .orderBy(asc(agentEvalRunTopics.createdAt));

// ❌ Bad: relational API with `with:`
return this.db.query.agentEvalRunTopics.findMany({
  where: eq(agentEvalRunTopics.runId, runId),
  with: { testCase: true, topic: true },
});
```

### Select with Aggregation

```typescript
// ✅ Good: select + leftJoin + groupBy
const rows = await this.db
  .select({
    id: agentEvalDatasets.id,
    name: agentEvalDatasets.name,
    testCaseCount: count(agentEvalTestCases.id).as('testCaseCount'),
  })
  .from(agentEvalDatasets)
  .leftJoin(agentEvalTestCases, eq(agentEvalDatasets.id, agentEvalTestCases.datasetId))
  .groupBy(agentEvalDatasets.id);
```

### One-to-Many (Separate Queries)

When you need a parent record with its children, use two queries instead of relational `with:`:

```typescript
// ✅ Good: two simple queries
const [dataset] = await this.db
  .select()
  .from(agentEvalDatasets)
  .where(eq(agentEvalDatasets.id, id))
  .limit(1);

if (!dataset) return undefined;

const testCases = await this.db
  .select()
  .from(agentEvalTestCases)
  .where(eq(agentEvalTestCases.datasetId, id))
  .orderBy(asc(agentEvalTestCases.sortOrder));

return { ...dataset, testCases };
```

## Database Migrations

See the `db-migrations` skill for the detailed migration guide.