Soft Deletes vs Hard Deletes

### Soft Delete Add `deleted_at` timestamp. **Pros**: Easy undo. Data retention. **Cons**: Every single query must include `WHERE deleted_at IS NULL`. Indexes get bloated with "dead" data. GDPR "Right to be Forgotten" is harder (you technically still have the data). ### Hard Delete Delete the row. **Pros**: Clean DB. Compliance is easy. **Cons**: No undo. **Best Practice**: Use Hard Delete + Archive Tables for audit logs.