1. A method for mapping a first plurality of source columns from a source file to a target file, each column of the source file having a header and a plurality of cells, each cell containing content, the target file having a second plurality of target columns, at least some of the target columns modeled to represent a third plurality of predefined entities, comprising, for each source column: evaluating heuristically whether the header for the source column matches at least one of the predefined entities, and if so, creating an initial mapping of the correspondence between the source column and the predefined entities; evaluating probabilistically, in response to a determination that the header for the source column does not match at least one of the predefined entities, whether the cell contents of the source column correspond to at least one of the predefined entities, and if so, creating an initial mapping of the correspondence between the source column and the predefined entities; assigning an entity score to the likelihood that the source column corresponds to the predefined entities in the initial mapping; evaluating at least one proximity indicator for the source column, wherein if the proximity indicator supports the initial mapping, then the entity score is increased, and wherein if the proximity indicator does not support the initial mapping, then the entity score is decreased; comparing the entity score for each predefined entity to a threshold, wherein if the threshold is met or exceeded, then creating a final mapping of the correspondence between the source column and the predefined entities, and wherein if the threshold is not met, then creating a final mapping of the correspondence between the source column and undefined entities; and transforming each source column to a target column in accord with the final mapping.