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

# Tracking New vs Modified Records in EDL

> Learn how to use first_seen_date and other fields to identify new versus pre-existing records in monthly EDL data deliveries.

For EDL customers receiving monthly data overwrites, tracking whether a record is new versus pre-existing and modified can be accomplished using the `first_seen_date` field.

## Using first\_seen\_date

The `first_seen_date` field in the PERMITS table indicates when Shovels first discovered the permit in our data collection process.

### Identifying New Records

Compare `first_seen_date` with your previous data delivery:

* Records where `first_seen_date` falls **after** your last update are **new**
* Records where `first_seen_date` falls **before** your last update are **existing**

### Example Logic

```sql theme={null}
-- New permits since last delivery (Jan 15)
SELECT * FROM permits
WHERE first_seen_date > '2024-01-15'
```

## Tracking Modifications

Currently, there is no specific flag indicating changes in records. To identify modifications to existing records:

1. **Maintain previous deliveries** - Keep a copy of your previous data
2. **Compare key fields** - Focus on fields that might change:
   * Status
   * Valuation
   * Dates
   * Other attributes
3. **Build comparison logic** - Create queries that identify differences

<Info>
  We're actively working on enhancing our data delivery system to include explicit change tracking flags in future releases.
</Info>

## Best Practices

1. Store the `first_seen_date` for your comparison baseline
2. Maintain at least one previous delivery for modification tracking
3. Focus comparisons on fields relevant to your use case
4. Consider building automated comparison pipelines

## Related Articles

* [Monthly deliveries](/docs/knowledge-base/edl/monthly-deliveries)
* [EDL overview](/docs/knowledge-base/edl/overview)