"Schema validation found non-datatype errors" error message when you try to open an InfoPath Form Web Part on an external list on a SharePoint 2010 server

Applies to: InfoPath 2010SharePoint Server 2010

Symptoms


Assume that you have an External List page on a Microsoft SharePoint Server 2010 server. The page uses the InfoPath Form Web Part. When you try to open an item on the page, you receive the following error message:
Schema validation found non-datatype errors.



Click Try Again to attempt to load the form again. If this error persists, contact the support team for the Web site.



Click Close to exit this message.



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Correlation ID:CID_string

Cause


This problem occurs because a required field in a SharePoint 2010 external list database has the following characteristics:
  • The field is marked as non-nullable.
  • The field can accept empty strings as valid input.
In this situation, Microsoft InfoPath 2010 treats empty strings and null entries as equivalent values. Therefore, these values are treated as invalid input.

Workaround


To work around this problem, if you have a database field that is marked as required when you define an operation on the external content type, make sure that the field contains values that are valid and nonblank.