Are Glue DDQL Rule Types Case Sensitive?

Question

# Issue

The [CustomSql DDQL Rule Type documentation](https://docs.aws.amazon.com/glue/latest/dg/dqdl-rule-types-CustomSql.html) shows examples using both "CustomS**ql**" and "CustomS**QL**" as the rule types.

However, when I used a capital "QL" this rule syntax, I received this error message in console:

**Syntax:** CustomS**QL**

**Error:**

```
Error encountered

InvalidInputException (status: 400): DataQuality rules cannot be parsed

See details

{ "message": "DataQuality rules cannot be parsed", "code": "InvalidInputException", "[__type]": "See error.__type for details.", "[Message]": "See error.Message for details.", "time": "2025-12-10T16:28:27.520Z", "requestId": "", "statusCode": 400, "retryable": false }
```

---

# Request

If DDQL Ruletypes are case sensitive, is there any way we can update the documentation to show only "CustomS**ql**" in examples? - with a loqwecase "ql" only?

re:Post Agent · Answer

AWS Glue Data Quality Definition Language (DQDL) rule types are indeed case sensitive. Based on the error you encountered when using "CustomSQL" instead of "CustomSql", it appears that the correct format requires the specific casing as "CustomSql" with a lowercase "ql".

This is consistent with how case sensitivity works in other AWS Glue components. For example, in AWS Glue transformations like FormatCase, there are specific case types that must be used exactly as defined: "CAPITAL", "LOWER", "UPPER", and "SENTENCE". Similarly, in AWS Glue DataBrew, case transformation operations like SENTENCE_CASE, LOWER_CASE, and CAPITAL_CASE must be specified with their exact casing.

The inconsistency in the documentation showing both "CustomSql" and "CustomSQL" is likely an error, and the correct format appears to be "CustomSql" based on your experience with the error message.  
**Sources**  
[FormatCase class - AWS Glue](https://docs.aws.amazon.com/glue/latest/dg/aws-glue-api-pyspark-transforms-FormatCase.html)  
[SENTENCE_CASE - AWS Glue DataBrew](https://docs.aws.amazon.com/databrew/latest/dg/recipe-actions.SENTENCE_CASE.html)  
[LOWER_CASE - AWS Glue DataBrew](https://docs.aws.amazon.com/databrew/latest/dg/recipe-actions.LOWER_CASE.html)  
[CAPITAL_CASE - AWS Glue DataBrew](https://docs.aws.amazon.com/databrew/latest/dg/recipe-actions.CAPITAL_CASE.html)

Are Glue DDQL Rule Types Case Sensitive?

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