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

# Schema Radar

Schema Radar is Datawise's post-deployment detection layer. It monitors schema changes across your connected warehouse, classifies them as breaking or safe, and shows you the full downstream blast radius.

## How It Works

On each ingestion run, Schema Radar:

1. Fetches the current schema for all tracked tables and views from your connected warehouse.
2. Compares it against the schema captured in the previous run.
3. Classifies each change: breaking, safe, or additive.
4. Resolves downstream impact using your lineage graph.
5. Records the change in an immutable history log.
6. Tracks mitigation by comparing subsequent ingestion runs.

## What Schema Radar Detects

| Change Type                                       | Classification  |
| ------------------------------------------------- | --------------- |
| Column removed                                    | Breaking        |
| Column renamed                                    | Breaking        |
| Data type changed to incompatible type            | Breaking        |
| Column nullability changed (not null to nullable) | Breaking        |
| Table or view dropped                             | Breaking        |
| New column added                                  | Safe (additive) |
| Data type widened (e.g., `INT` to `BIGINT`)       | Safe            |
| Table or view created                             | Safe (additive) |

## Downstream Impact

When a breaking change is detected, Schema Radar resolves which downstream assets are affected:

* **dbt models** that `SELECT` from or `ref()` the changed table.
* **Tableau workbooks** that connect to downstream dbt models or directly to the changed table.
* **Power BI reports** with connections to affected tables or models.

## Mitigation Tracking

After a breaking change is detected, Datawise compares subsequent ingestion runs to determine if the schema has been reverted or a downstream asset has been updated. Mitigation status updates automatically on subsequent runs.

## Change History

The Schema Radar change history is immutable. Once a change is recorded, it stays in the log — giving you an accurate audit trail of what changed, when, and what was impacted.

## Viewing Schema Radar

Go to **Schema Radar** in the left navigation. Filter by asset, change type, date range, or status. Click any change to open the detail view with the full before/after schema diff, downstream impact tree, and mitigation status.

From any change, click **View in Lineage** to open the Lineage view scoped to that specific detection event.

## Frequently Asked Questions

<AccordionGroup>
  <Accordion title="How often does Schema Radar run?">
    On the schedule you configure for each warehouse connector. We recommend daily. Trigger a manual run from the Connectors page at any time.
  </Accordion>

  <Accordion title="Can I delete a change from the history?">
    No. Schema Radar history is immutable by design.
  </Accordion>

  <Accordion title="Does Schema Radar detect changes to views?">
    Yes. View schema changes are detected the same way as table changes.
  </Accordion>
</AccordionGroup>