# ColumnSchema
<a name="API_ColumnSchema"></a>

Metadata for a column.

## Contents
<a name="API_ColumnSchema_Contents"></a>

 ** columnName **   <a name="API-Type-ColumnSchema-columnName"></a>
The name of a column.  
Type: String  
Length Constraints: Minimum length of 1. Maximum length of 128.  
Pattern: `[a-zA-Z0-9_](([a-zA-Z0-9_ ]+-)*([a-zA-Z0-9_ ]+))?`   
Required: Yes

 ** columnTypes **   <a name="API-Type-ColumnSchema-columnTypes"></a>
The data type of column.  
Type: Array of strings  
Array Members: Fixed number of 1 item.  
Valid Values: `USER_ID | ITEM_ID | TIMESTAMP | CATEGORICAL_FEATURE | NUMERICAL_FEATURE`   
Required: Yes

## See Also
<a name="API_ColumnSchema_SeeAlso"></a>

For more information about using this API in one of the language-specific AWS SDKs, see the following:
+  [AWS SDK for C\$1\$1](https://docs.aws.amazon.com/goto/SdkForCpp/cleanroomsml-2023-09-06/ColumnSchema) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/cleanroomsml-2023-09-06/ColumnSchema) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/cleanroomsml-2023-09-06/ColumnSchema)