# Create View Worker

Processes view creation jobs to create database views from queries.

## Overview

The create view worker creates database views based on SQL queries, allowing dynamic datasets that update when source data changes.

## Job Type

`create_view`

## Input Parameters

```json
{
  "source_dataset_id": 123,
  "query": "SELECT * FROM spatial_data_123 WHERE properties->>'category' = 'A'",
  "output_dataset_id": 124
}
```

### Parameters

- `source_dataset_id` (required): Source dataset ID
- `query` (required): SQL query to create view from
- `output_dataset_id` (required): Output dataset ID

## Output

Creates a new dataset backed by a database view:

- View created in `spatial_data` schema
- Dataset metadata in `spatial_files` table
- View updates automatically when source data changes

## Use Cases

- Filtered datasets
- Joined datasets
- Aggregated datasets
- Computed datasets

## Example

```bash
# Enqueue a create view job via API
curl -X POST "https://example.com/api/create_view_run.php" \
  -H "Content-Type: application/json" \
  -d '{
    "source_dataset_id": 123,
    "query": "SELECT * FROM spatial_data_123 WHERE properties->>'\''category'\'' = '\''A'\''",
    "output_dataset_id": 124
  }'
```

## Background Jobs

This analysis runs as a background job. The worker:

1. Fetches queued `create_view` jobs
2. Validates input parameters
3. Validates SQL query
4. Creates database view
5. Creates dataset metadata
6. Marks job as completed

## Performance Considerations

- Views don't store data, so creation is fast
- Query performance depends on underlying data
- Complex queries may slow view access
- Consider materialized views for expensive queries

## Related Documentation

- [Analysis API](../api/analysis.md)
- [Workers Overview](index.md)