# Migrator

Data-only migration tool between Postgres and SQLite using Drizzle.

## What it does

- Copies data from source to target
- Does NOT create or alter tables
- Overwrites target data if any rows exist (via `DELETE FROM` in dependency-safe order)

## Requirements

- Tables must already exist on the target database
- Schema must match the backend Drizzle schemas

## Usage

Run from repo root:

```bash
bun --cwd apps/migrator run migrate --from postgres --to sqlite --source "<PG_URL>" --target "<SQLITE_PATH>"
```

```bash
bun --cwd apps/migrator run migrate --from sqlite --to postgres --source "<SQLITE_PATH>" --target "<PG_URL>"
```

### Flags

- `--from`: `postgres` or `sqlite`
- `--to`: `postgres` or `sqlite`
- `--source`: Postgres connection string or SQLite file path
- `--target`: Postgres connection string or SQLite file path
- `--batch`: optional batch size (default: `500`)

## Examples

```bash
bun --cwd apps/migrator run migrate \
  --from postgres \
  --to sqlite \
  --source "postgres://user:pass@host:5432/db" \
  --target "./sqlite.db"
```

```bash
bun --cwd apps/migrator run migrate \
  --from sqlite \
  --to postgres \
  --source "./sqlite.db" \
  --target "postgres://user:pass@host:5432/db" \
  --batch 1000
```

## Notes

- IDs are copied as-is to preserve relationships.
- For Postgres targets, sequences may need manual reset after import.