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

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

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

Foreign Keys

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

Timestamps

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

Indexes

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

Type Inference

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

Example Pattern

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)

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

// ✅ 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

// ✅ 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

// ✅ 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::

// ✅ 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 references/db-migrations.md for detailed migration guide.

# Generate migrations
bun run db:generate

# After modifying SQL (e.g., adding IF NOT EXISTS)
bun run db:generate:client

Migration Best Practices

All migration SQL must be idempotent (safe to re-run):

-- ✅ Tables: IF NOT EXISTS
CREATE TABLE IF NOT EXISTS "agent_eval_runs" (...);

-- ✅ Columns: IF NOT EXISTS / IF EXISTS
ALTER TABLE "users" ADD COLUMN IF NOT EXISTS "avatar" text;
ALTER TABLE "users" DROP COLUMN IF EXISTS "old_field";

-- ✅ Foreign keys: DROP IF EXISTS + ADD (no IF NOT EXISTS for constraints)
ALTER TABLE "t" DROP CONSTRAINT IF EXISTS "t_fk";
ALTER TABLE "t" ADD CONSTRAINT "t_fk" FOREIGN KEY ("col") REFERENCES "ref"("id") ON DELETE cascade;

-- ✅ Indexes: IF NOT EXISTS
CREATE INDEX IF NOT EXISTS "users_email_idx" ON "users" ("email");

-- ❌ Non-idempotent (will fail on re-run)
CREATE TABLE "agent_eval_runs" (...);
ALTER TABLE "users" ADD COLUMN "avatar" text;
ALTER TABLE "t" ADD CONSTRAINT "t_fk" FOREIGN KEY ...;

Rename migration files meaningfully: 0046_meaningless.sql → 0046_user_add_avatar.sql