Embodiments of the invention comprise a method and apparatus for transforming data. Systems implementing the invention allow for loading the data from one or more source tables into one or more destination tables. The system allows for parsing source data fields, defining new source data fields, combining source fields to create source field combinations, and combining destination fields to create destination field combinations. The system allows for mapping source fields and values to destination fields and values, where either the source fields and values or destination fields and values may be field and value combinations, and allows for transforming field values based on destination field type. The tools provided in a system implementing the invention provide a user the ability to intervene at each step during the data transform task. A user may manually input a hierarchy definition, a specific mapping, define rules for combining data fields, or define rules for converting data values.