1. A computer-implemented system for providing bulk data transfers between one or more data stores, comprising: a data integration server coupled with the one or more data stores, the data integration server comprising: a plurality of programmatic source interfaces coupled with one or more source data stores, wherein the plurality of programmatic source interfaces are defined according to a source interface specification and are exposed during the bulk data transfer, one or more data entities are extracted from the one or more source data stores; and a plurality of programmatic target interfaces coupled with one or more target data stores, wherein the plurality of programmatic target interfaces are defined according to a target interface specification and are exposed during the bulk data transfer, one or more of the extracted data entities are loaded into the one or more target data stores; one or more relational interfaces used as alternatives to the plurality of programmatic source interfaces and the plurality of programmatic target interfaces, each of the one or more relational interfaces coupled with a corresponding relational data store and exposed within the data integration server during the bulk data transfer, the data integration server reads the one or more data entities directly from and writes the one or more data entities directly to the one or more relational data stores during the bulk data transfer when the data integration server determines whether to use the one or more relational interfaces or the plurality of programmatic source interfaces and the plurality of programmatic target interfaces based on file processing time and one or more performance requirements; and one or more transformation interfaces that are exposed within the data integration server during the bulk data transfer, the one or more transformation interfaces uncoupling transformation logic from one or more of the plurality of programmatic source interfaces and one or more of the plurality of programmatic target interfaces.