> For the complete MongoDB documentation index, see www.mongodb.com/docs/llms.txt

# Set Language Specific Rules for String Comparison

Use the [Collation](https://www.mongodb.com/docs/manual/reference/collation/) query bar option to specify language-specific rules for string comparison, such as rules for lettercase and accent marks.

**Important: Feature unavailable in Flex Clusters**

Flex clusters don't support this feature at this time. To learn more, see [Atlas Flex Limitations.](https://www.mongodb.com/docs/atlas/reference/flex-limitations.md#std-label-flex-cluster-limitations)

## Set Collation

1. In Atlas, go to the Data Explorer page for your project.

   If it's not already displayed, select the organization that contains your project from the  Organizations menu in the navigation bar.

   If it's not already displayed, select your project from the Projects menu in the navigation bar.

   In the sidebar, click Data Explorer under the Database heading.

   The [Data Explorer](https://cloud.mongodb.com/go?l=https%3A%2F%2Fcloud.mongodb.com%2Fv2%2F%3Cproject%3E%23%2Fmetrics%2FreplicaSet%2F%3Creplset%3E%2Fexplorer) displays.

   IMPORTANT: You can also click the name of a cluster to open the Cluster sidebar, and then click Data Explorer under the Shortcuts heading.

2. Set the collation.

   Select the collection.

   In the Query Bar, click Options.

   Enter the `locale` field in the collation document to specify the [ICU Locale code](http://userguide.icu-project.org/locale) for the desired language in the Collation field.

   **Example:**

   To use the `pinyin` variant of the Chinese collation, use the following collation document:

   ```javascript
   { "locale" : "zh@collation=pinyin" }
   ```

   As you type, the Find button is disabled and the Collation label turns red until a valid query is entered.

   Click Find to run the query and view the updated results.

## Clear the Query

To clear the query bar and the results of the query, click Reset.

## To Learn More

- See the supported languages and locales section in the [MongoDB Manual.](https://www.mongodb.com/docs/manual/reference/collation-locales-defaults/#collation-languages-locales)

- See the possible fields in a collation document in the [MongoDB Manual.](https://www.mongodb.com/docs/manual/reference/collation/#collation-document-fields)