# ImportDataRule
<a name="API_S3Files_ImportDataRule"></a>

Specifies a rule that controls how data is imported from S3 into the file system.

## Contents
<a name="API_S3Files_ImportDataRule_Contents"></a>

 ** prefix **   <a name="AmazonS3-Type-S3Files_ImportDataRule-prefix"></a>
The S3 key prefix that scopes this import rule. Only objects with keys beginning with this prefix are subject to the rule.  
Type: String  
Pattern: `(|.*/)`   
Required: Yes

 ** sizeLessThan **   <a name="AmazonS3-Type-S3Files_ImportDataRule-sizeLessThan"></a>
The upper size limit in bytes for this import rule. Only objects with a size strictly less than this value will have data imported into the file system.  
Type: Long  
Valid Range: Minimum value of 0. Maximum value of 52673613135872.  
Required: Yes

 ** trigger **   <a name="AmazonS3-Type-S3Files_ImportDataRule-trigger"></a>
The event that triggers data import. Valid values are `ON_DIRECTORY_FIRST_ACCESS` (import when a directory is first accessed) and `ON_FILE_ACCESS` (import when a file is accessed).  
Type: String  
Valid Values: `ON_DIRECTORY_FIRST_ACCESS | ON_FILE_ACCESS`   
Required: Yes

## See Also
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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/s3files-2025-05-05/ImportDataRule) 
+  [AWS SDK for Java V2](https://docs.aws.amazon.com/goto/SdkForJavaV2/s3files-2025-05-05/ImportDataRule) 
+  [AWS SDK for Ruby V3](https://docs.aws.amazon.com/goto/SdkForRubyV3/s3files-2025-05-05/ImportDataRule)