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

# Local DB Instances

> Instance-level SQLite operations for task occurrences.

# Local DB Instances

The local-db-instances.ts module is the "Temporal Auditor" -- it manages the lifecycle of individual task occurrences within the local SQLite cache.

***

## Orphan Survival

The schema has zero foreign key constraints. Instances are first-class citizens that can exist with or without a parent task. When updating an orphaned instance, the module falls back to the raw Convex task\_id:

```typescript theme={null}
const parentTask = await db.getFirstAsync(
  "SELECT id FROM local_tasks WHERE convex_id = ?", [instance.task_id]
);
const localTaskId = parentTask?.id ?? instance.task_id; // Fallback for orphans
```

***

## Core Operations

| Function                          | Purpose                                                             |
| :-------------------------------- | :------------------------------------------------------------------ |
| updateSingleInstanceInLocalDb()   | Atomic delete-then-insert (clobber and spawn) for a single instance |
| deleteSingleInstanceFromLocalDb() | Removes an instance by its Convex ID                                |

***

## Atomic Clobber and Spawn

Updates use a "delete then insert" strategy within a transaction. This guarantees that even if the column set changes between versions, the row is always fresh and complete.