1. A data transformation system comprising: a schema inference module configured to dynamically create a cumulative schema for objects retrieved from a first data source, wherein: each of the retrieved objects includes (i) data and (ii) metadata describing the data, and dynamically creating the cumulative schema includes, for each object of the retrieved objects, (i) inferring a schema from the object and (ii) selectively updating the cumulative schema to describe the object according to the inferred schema; and an export module configured to output the data of the retrieved objects to a data destination system according to the cumulative schema.