> ## 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.

> [!NOTE]
>
> Supported in Databricks with Unity Catalog only. \\
>
> Not supported in Athena or Trino.

```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
```


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