> ## Documentation Index
> Fetch the complete documentation index at: https://supaschema.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# selfcheck

> Compare live-catalog extraction against the database engine representation.

Use `selfcheck` when evaluating supaschema against an existing database or after upgrading the engine.

The command extracts a live catalog, re-renders the modeled SQL, re-extracts it, and reports identity normalization gaps.

## Use this when

* You are validating catalog normalization.
* A provider-specific object shape may need investigation.
* An upgrade should be checked against a real database.
* You need diagnostics for engine parity work.

## Run it

```bash theme={null}
npx supaschema selfcheck --database-url "$DATABASE_URL"
```

`selfcheck` is a diagnostic tool, not a deployment gate. Review mismatches before deciding whether they matter.

## Flags

<ParamField path="--database-url" type="url">
  PostgreSQL URL to extract. Defaults to normal database URL resolution.
</ParamField>

## Exit codes

| Code | Meaning                                       |
| ---- | --------------------------------------------- |
| `0`  | Selfcheck completed without error diagnostics |
| `1`  | Runtime failure or missing database URL       |
| `2`  | Diagnostics contained an error                |

## Related

<CardGroup cols={2}>
  <Card title="Inspect" icon="scan-search" href="/docs/commands/inspect">
    Print the extracted model directly.
  </Card>

  <Card title="Fingerprint" icon="fingerprint" href="/docs/commands/fingerprint">
    Compare normalized model hashes.
  </Card>

  <Card title="Corpus" icon="database-zap" href="/docs/commands/corpus">
    Run dirty-real regression coverage.
  </Card>

  <Card title="Support matrix" icon="table" href="/docs/reference/support-matrix">
    Check modeled object coverage.
  </Card>
</CardGroup>