A system and method for extracting data from an input source, transforming the data, and loading the transformed data to an output destination. A schema contract including constraints is used to validate a set of input data column types and translate them into a set of actual types. Mapping data in the schema contract enable mapping input data columns to data columns used by data integration components. The constraints and mapping data provide flexibility in transforming sets of data having different sets of input data column types, while providing a fixed set of types for use during dataflow executions. Flexibility may enable optional columns, sets of one or more columns, varying arrangements of columns, and variations in type definitions of each column.