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

# Schema changes

`elementary.schema_changes`

Executes schema changes monitor that alerts on deleted table, deleted or added columns, or change of data type of a column.
Data Types note: Snowflake, Redshift and Postgres all has "synonym" data types, like `VARCHAR` and `TEXT` in Snowflake. These will be considered as equals by the tests. Types are converted internally to deal with this.

<Info>
  Supported in Databricks with Unity Catalog only. <br />
  Not supported in Athena or Trino.
</Info>

<RequestExample>
  ```yml Models theme={null}
  version: 2

  models:
    - name: < model name >
      data_tests:
        - elementary.schema_changes
  ```

  ```yml Models example theme={null}
  version: 2

  models:
    - name: login_events
      data_tests:
        - elementary.schema_changes:
            config:
              tags: ["elementary"]
              severity: warn
  ```
</RequestExample>