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I'm trying to read some documents from a mongo database and parse the schema in a spark DataFrame. So far I have had success reading from mongo and transforming the resulting mongoRDD into a DataFrame using a schema defined by case classes, but there's a scenario where the mongo collection has a field containing multiple datatypes (array of strings vs. array of nested objects). So far I have been simply parsing the field as a string, then using spark sql's from_json() to parse the nested objects in the new schema, but I am finding that when a field does not conform to the schema, it returns null for all fields in the schema - not simply the field that does not conform. Is there a way to parse this so that only fields not matching the schema will return null?