> For the complete documentation index, see [llms.txt](https://docs.hipersnipe.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.hipersnipe.com/architecture/database.md).

# Database and migrations

## Storage

* **Engine:** SQLite 3
* **File:** `users.db` (git-ignored, live production data)
* **Mode:** WAL (Write-Ahead Logging) for multi-process access

## Schema ownership

| Layer          | Location                                                           |
| -------------- | ------------------------------------------------------------------ |
| Table creation | `db/core.py` → `create_db_and_table()`                             |
| Migrations     | `db_handler_aio.py` → `init_db()` / `update_schema()`              |
| DAO modules    | `db/users_dao.py`, `db/limits_dao.py`, `db/positions_dao.py`, etc. |

## Migration rules (strict)

1. **Never drop** `users.db` in production.
2. **Auto-migrate only** — forward-only `ALTER TABLE ADD COLUMN` on startup.
3. **Idempotent** — safe to run every boot.

Example pattern:

```python
async with db.execute("PRAGMA table_info(users)") as cur:
    cols = {row[1] for row in await cur.fetchall()}
if "new_column" not in cols:
    await db.execute("ALTER TABLE users ADD COLUMN new_column TEXT DEFAULT ''")
```

## Key tables

| Table / field       | Contents                                                                  |
| ------------------- | ------------------------------------------------------------------------- |
| `users`             | Telegram ID, encrypted private key, wallet address, trades JSON, settings |
| `limit_orders`      | Pending limit buy/sell orders                                             |
| `auto_sell_configs` | Trading Shield per user+token                                             |
| `dca_orders`        | Recurring buy schedules                                                   |
| `copy_targets`      | Wallets to mirror                                                         |
| `global_config`     | Infra keys, sniper config, fee settings                                   |
| `partners`          | Channel ID → referral code mappings                                       |

## Trades JSON structure

Per-mint trade history stored in `users.trades`:

```json
{
  "MINT_ADDRESS": {
    "trades": [
      {"type": "buy", "sol_amount": 0.5, "token_amount": 1000000, "timestamp": 1710000000},
      {"type": "sell", "sol_amount": 0.3, "token_amount": 500000, "timestamp": 1710003600}
    ],
    "last_cycle_closed_at": 0
  }
}
```

`pnl_tracker.py` replays this JSON with cycle reset logic when balance hits dust.

## Concurrency

* `_db_lock` serializes writes in single process
* Cross-process: retry on `database is locked` (up to 5 attempts)
* Connection timeout: 30 seconds

## Backup

Back up `users.db` regularly in production. The file contains encrypted private keys—treat backups as highly sensitive.

## Related

* [Security model](/architecture/security.md)
* [Development: contributing](/development/contributing.md)


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