# Database Postgres

> Drizzle schema, repositories, RLS, SqlClient wiring, Postgres migrations, psql / reset, or platform mappers (toDomain* / toInsertRow).

- Skill: `latitude-dev/database-postgres` (Agent Skill)
- Install (CLI): `npx skillmds@latest add latitude-dev/database-postgres`
- Raw SKILL.md: https://api.skillmd.com/api/skills/latitude-dev/database-postgres/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: latitude-dev (https://skillmd.com/u/latitude-dev)
- Updated: 2026-09-10
- Page: https://skillmd.com/skills/latitude-dev/database-postgres

---


# Postgres, SqlClient, schema, migrations, mappers

**When to use:** Drizzle schema, repositories, RLS, SqlClient wiring, Postgres migrations, `psql` / reset, or platform mappers (`toDomain`* / `toInsertRow`).

## Database patterns (Postgres)

- Postgres adapter stack uses Drizzle ORM in `packages/platform/db-postgres`
- Domain models are independent from table/row shapes
- Mapping from DB rows to domain objects belongs in platform adapters
- **Apps use SqlClient for all DB access**: Boundaries provide `SqlClientLive` with organization context for RLS enforcement

## SqlClient and row-level security (RLS)

All Postgres access flows through `SqlClient`—a domain-level service that abstracts database operations and enforces organization scoping via RLS.

**Architecture:**

- **Domain Layer** (`@domain/shared`): `SqlClient` interface with `transaction()` and `query()` methods
- **Platform Layer** (`@platform/db-postgres`): `SqlClientLive` implementation with automatic RLS context setting
- **App Layer** (`apps/`*): Boundaries provide `SqlClientLive` with the request's organization context

**Key behaviors:**

- Every transaction automatically sets `app.current_organization_id` session variable
- RLS policies filter all queries by this organization ID at the database level
- Nested transactions share the same connection (pass-through proxy—no nested transaction overhead)
- Domain errors propagate through Effect error channel; database errors become `RepositoryError`
- On effect failure, `SqlClientLive` still awaits the Drizzle transaction promise so the connection returns to the pool; if the driver surfaces a **different** error than the Effect failure (for example rollback/commit), that secondary error is logged via `@repo/observability` while the original failure remains the propagated error

**Usage in boundaries (apps):**

```typescript
// packages/operations/src/operations/projects.ts
import { SqlClientLive } from "@platform/db-postgres"
import { ProjectRepositoryLive } from "@platform/db-postgres"

app.openapi(createProjectRoute, async (c) => {
  const project = await Effect.runPromise(
    createProjectUseCase(input).pipe(
      Effect.provide(ProjectRepositoryLive),
      Effect.provide(SqlClientLive(c.var.postgresClient, c.var.organization.id)),
    ),
  )
  return c.json(toProjectResponse(project), 201)
})
```

```typescript
// apps/web/src/domains/projects/projects.functions.ts
import { getPostgresClient } from "../../server/clients.ts"

export const createProject = createServerFn({ method: "POST" })
  .handler(async ({ data }) => {
    const { organizationId } = await requireSession()
    const client = getPostgresClient()

    const project = await Effect.runPromise(
      createProjectUseCase({...}).pipe(
        Effect.provide(ProjectRepositoryLive),
        Effect.provide(SqlClientLive(client, organizationId)),
      )
    )
    return toRecord(project)
  })
```

**Usage in use-cases (multi-operation transactions):**

```typescript
// packages/domain/auth/src/use-cases/complete-auth-intent.ts
export const completeAuthIntentUseCase = (input) =>
  Effect.gen(function* () {
    const sqlClient = yield* SqlClient

    yield* sqlClient.transaction(handleIntentByType(intent, input.session))
  })

const handleSignup = (intent, session) =>
  Effect.gen(function* () {
    const users = yield* UserRepository
    const memberships = yield* MembershipRepository

    const organization = yield* createOrganizationUseCase({...})
    yield* memberships.save(createMembership({...}))
    yield* users.setNameIfMissing({...})
  })
```

**Usage in repositories (single operations):**

Repository methods must resolve `SqlClient` inside each call — never capture it at layer build. See the "Never capture scope-bound services at layer build" rule in the **Effect and errors** skill.

```typescript
// packages/platform/db-postgres/src/repositories/project-repository.ts
export const ProjectRepositoryLive = Layer.effect(
  ProjectRepository,
  Effect.gen(function* () {
    return {
      findById: (id) =>
        Effect.gen(function* () {
          const sqlClient = (yield* SqlClient) as SqlClientShape<Operator>
          return yield* sqlClient
            .query((db, organizationId) =>
              db
                .select()
                .from(projects)
                .where(and(eq(projects.organizationId, organizationId), eq(projects.id, id)))
                .limit(1),
            )
            .pipe(Effect.flatMap(...))
        }),

      save: (project) =>
        Effect.gen(function* () {
          const sqlClient = (yield* SqlClient) as SqlClientShape<Operator>
          yield* sqlClient.query((db, organizationId) =>
            db.insert(projects).values({ ...row, organizationId }).onConflictDoUpdate({...})
          )
        }),
    }
  })
)
```

The layer-build effect doesn't `yield* SqlClient` at all — the dependency is declared via each method's `R` channel, and resolved per call. A build-time yield is redundant and (if captured) re-introduces the very bug this pattern avoids.

### Pull `organizationId` from the RLS context, not from method params

The `query((db, organizationId) => …)` callback receives the active organization id from the `SqlClient`'s RLS context. **Use that value** in `WHERE` predicates and `INSERT … VALUES` rows. Don't accept `organizationId` as a parameter on the repository method just to re-thread it into the SQL.

Why:

- **Consistency** — every repo call is scoped the same way regardless of which caller invokes it. Use-cases don't get to pick a different org from the one their request authenticated against.
- **Defense in depth alongside RLS** — RLS already filters rows by `app.current_organization_id`, but the explicit predicate makes intent obvious in the query plan and catches accidental "I forgot RLS is on" mistakes during code review.
- **Insert safety** — for `create`/`save` methods, writing the RLS-supplied org id (instead of trusting `entity.organizationId`) prevents a caller from fabricating an entity for a different org and inserting it through the right org's transaction.

```ts
// Good — orgId comes from RLS, name reflects the actual action.
findMemberByEmail: (email: string) =>
  Effect.gen(function* () {
    const sqlClient = (yield* SqlClient) as SqlClientShape<Operator>
    return yield* sqlClient.query((db, organizationId) =>
      db
        .select({ id: members.id })
        .from(members)
        .where(and(eq(members.organizationId, organizationId), eq(members.email, email.toLowerCase())))
        .limit(1),
    )
  }),

create: (invitation: Invitation) =>
  Effect.gen(function* () {
    const sqlClient = (yield* SqlClient) as SqlClientShape<Operator>
    yield* sqlClient.query((db, organizationId) =>
      db.insert(invitations).values({ ...row, organizationId }),
    )
  }),

// Bad — orgId is a redundant input the caller could mis-pass.
findMemberByEmail: ({ email, organizationId }: { email: string; organizationId: OrganizationId }) =>
  /* … query((db) => …where(eq(members.organizationId, organizationId))) */,

// Bad — trusts the entity for the inserted org id; nothing stops a caller
// from passing an entity for a different org through this org's transaction.
create: (invitation: Invitation) =>
  /* … query((db) => db.insert(invitations).values({ ...invitation })) */,
```

Naming: if dropping the explicit param makes the method's name redundant (e.g. `listPendingByOrganizationId` → `listPending`), rename it. The repository contract should describe what the method *does*, not which scope it's bound to — the scope is the RLS context by construction.

**Exceptions** — methods that legitimately operate outside the current RLS org are rare and should be obvious from the name and a comment:
- `findPublicPendingPreviewById(invitationId)` — invite landing pages query before the invitee has authenticated, so there is no RLS context to lean on. Document the cross-org scope explicitly.
- Admin/maintenance scripts that go through `withAdmin(...)` rather than `withPostgres(...)`.

The repository port's method signatures must list `SqlClient` in their `R` channel:

```typescript
// packages/domain/projects/src/ports/project-repository.ts
export interface ProjectRepositoryShape {
  findById(id: ProjectId): Effect.Effect<Project, NotFoundError | RepositoryError, SqlClient>
  save(project: Project): Effect.Effect<void, RepositoryError, SqlClient>
}
```

`SqlClient` is marked `@effect-leakable-service` in `@domain/shared`, so the Effect linter accepts this intentional leak. Callers already have `SqlClient` in their `R` (via `withPostgres(...)` at the boundary), so the leak is invisible to them.

## Postgres management

Connect to the development database:

```bash
docker compose exec postgres psql -U latitude -d latitude_development
```

Reset only the Postgres volume (without affecting other services):

```bash
pnpm --filter @platform/db-postgres pg:reset
```

This runs `docker/reset-postgres.sh` which stops postgres, removes the `data-llm_postgres_data` volume, restarts postgres, waits for it to be ready, runs migrations, and seeds the database.

## Postgres schema conventions

All Drizzle table definitions in `packages/platform/db-postgres/src/schema/` **must** follow these rules. Shared helpers live in `schemaHelpers.ts`.

Organization-scoped Postgres tables must use the repository RLS conventions.

1. **Use `latitudeSchema`** — never create a local `pgSchema("latitude")`. Import `latitudeSchema` from `../schemaHelpers.ts`.
2. **Use `cuid("id").primaryKey()`** — every table's primary key must use the `cuid()` helper (`varchar(24)` with auto-generated CUID2).
3. **Use `tzTimestamp(name)`** — never use raw `timestamp(name, { withTimezone: true })`. Import `tzTimestamp` from the helpers.
4. **Use `...timestamps()`** — every table that has `createdAt`/`updatedAt` must spread the `timestamps()` helper (includes `$onUpdateFn` on `updatedAt`).
5. **Use `organizationRLSPolicy(tableName)`** — every table with an `organization_id` column must include this helper in its third argument to enable row-level security.
6. **No foreign keys** — new Postgres tables must not add foreign key constraints. Do not use `.references()` or manually create `FOREIGN KEY` constraints. Referential integrity is enforced at the application/domain layer. Use indexes on relationship columns instead (e.g. `index().on(t.datasetId)` rather than `.references(() => datasets.id)`).

```typescript
// ✅ Good - follows all conventions
export const projects = latitudeSchema.table(
  "projects",
  {
    id: cuid("id").primaryKey(),
    organizationId: text("organization_id").notNull(),
    name: varchar("name", { length: 256 }).notNull(),
    deletedAt: tzTimestamp("deleted_at"),
    ...timestamps(),
  },
  () => [organizationRLSPolicy("projects")],
)
```

## Database migrations (Drizzle Kit)

### Migration execution safety (agents)

Do **not** run Postgres migration commands (`pg:generate`, `pg:generate:custom`, `pg:migrate`, etc.) unless the user explicitly asked in this conversation. If migrations are needed but not requested, explain and wait for confirmation. ClickHouse / Weaviate follow the same policy in their respective skills.

**Always use drizzle-kit for migrations.** Never create manual SQL files in the drizzle folder.

**Schema changes:**

```bash
# Generate migration from schema changes
pnpm --filter @platform/db-postgres pg:generate "<name>"

# Create empty migration for custom SQL (RLS policies, seed data, etc.)
pnpm --filter @platform/db-postgres pg:generate:custom "<name>"

# Apply migrations
pnpm --filter @platform/db-postgres pg:migrate
```

**Key points:**

- Name is slugified automatically; always quote multi-word names (e.g. `"add users table"` → `add-users-table`)
- Postgres migration history is append-only in this repository. Do not edit existing Drizzle migration files; change the schema and generate a new migration instead.
- For additive changes to existing tables, prefer ordinary generated `ALTER TABLE` migrations over bespoke backfill choreography unless the change truly requires data rewriting.
- Never manually create SQL files in the drizzle folder
- Use `IF NOT EXISTS` in custom SQL for idempotency
- Migrations are tracked in `drizzle.__drizzle_migrations` table

## Repository port naming

Domain repository ports and method naming conventions (including Effect result shapes and when to use `listBy`* vs `findBy*`) live in [dev-docs/repositories.md](../../../dev-docs/repositories.md). Prefer that vocabulary for new Postgres-backed ports and when renaming existing methods.

## Mapper conventions

When writing `toDomain*` and `toInsertRow` functions in platform repositories:

- **Never hardcode field values.** Every field on the domain entity must be read from the DB row (`row.fieldName`), not assigned a literal (`null`, `""`, `new Date()`). If a field has no backing column, that is a schema gap — add the column or remove the field from the domain type.
- **Never use `as EntityType` casts** on mapper return values. These bypass TypeScript's structural check and hide type mismatches. Let the return type be inferred or explicitly annotated — the compiler will catch missing or incompatible fields.
- **Never coerce nullable columns** with `?? fallback` to satisfy a non-nullable domain type. Surface the mismatch: either make the column `notNull()` or make the domain field nullable.
- `**toInsertRow` must round-trip.** Every field written by `toInsertRow` should be readable by `toDomain`*, and vice versa. A field present in the domain type but absent from `toInsertRow` means data is silently discarded on write.