> For the complete documentation index, see [llms.txt](https://docs.snowddl.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.snowddl.com/basic/yaml-configs/materialized-view.md).

# MATERIALIZED VIEW

Config path: `/<database>/<schema>/materialized_view/<name>.yaml`

Example:

```yaml
text: |-
  SELECT id, name
  FROM test_ext_table_1

is_secure: true
```

## Schema

* **columns** (dict)
  * *{key}* (ident) - column name
  * *{value}* (str) - column comment
* <mark style="background-color:red;">**text**</mark> (str) - view text
* **is\_secure** (bool) - is view secure
* **cluster\_by** (list)
  * *{items}* (str) - SQL expressions for CLUSTER BY
* **comment** (str)

## Policy reference parameters

* **aggregation\_policy** (dict)
  * **policy\_name** (ident) - name of [AGGREGATION POLICY](/basic/yaml-configs/aggregation-policy.md)
  * **columns** (list)
    * *{items}* (ident) - optional reference column names defining "entity"
* **join\_policy** (dict)
  * **policy\_name** (ident) - name of [JOIN POLICY](/basic/yaml-configs/join-policy.md)
  * **columns** (list)
    * *{items}* (ident) - optional allowed join keys
* **masking\_policies** (list)
  * *{items}* (dict)
    * **policy\_name** (ident) - name of [MASKING POLICY](/basic/yaml-configs/masking-policy.md)
    * **columns** (list)
      * *{items}* (ident) - reference column names
* **projection\_policies** (list)
  * *{items}* (dict)
    * **policy\_name** (ident) - name of [PROJECTION POLICY](/basic/yaml-configs/projection-policy.md)
    * **column** (ident) - reference column name
* **row\_access\_policy** (dict)
  * **policy\_name** (ident) - name of [ROW ACCESS POLICY](/basic/yaml-configs/row-access-policy.md)
  * **columns** (list)
    * *{items}* (ident) - reference column names

## Usage notes

1. If you include **cluster\_by**, **columns** are also required.
2. Maintenance of materialized views implicitly incurs [additional costs](https://docs.snowflake.com/en/user-guide/views-materialized.html#label-materialized-views-maintenance-billing).
3. Invalid materialized views will be re-created automatically.

## Links

* [CREATE MATERIALIZED VIEW](https://docs.snowflake.com/en/sql-reference/sql/create-materialized-view.html)
* [SHOW MATERIALIZED VIEWS](https://docs.snowflake.com/en/sql-reference/sql/show-materialized-views.html)
* [Working with Materialized Views](https://docs.snowflake.com/en/user-guide/views-materialized.html)
* [Parser & JSON Schema (GitHub)](https://github.com/littleK0i/SnowDDL/blob/master/snowddl/parser/materialized_view.py)