An apparatus and article of manufacture for determining a target data type in an environment having a plurality of levels are provided. Zero or more intermediate levels are between the source level and the target level. A target data type representing the transformation of a data type of an associated datum as the datum passes from the source level through the zero or more intermediate levels to the target level is generated. In another aspect of the invention, the datum is assigned to the target level in accordance with the target data type. In yet another aspect of the invention, the target data type is passed with the associated datum, via the zero or more intermediate levels to the target level.