A method and apparatus for programming a computer to execute a batch data processing procedure using a computing device having at least a processor, a memory, a display device and an input device. The memory stores a plurality of functions arranged to process individual data messages or batches of data messages. A function is selected from the plurality of functions and retrieved from the memory. A data flow diagram is arranged on the display, in response to developer input, to specify a process. The data flow diagram includes a function icon corresponding to the selected function, at least one data icon corresponding to a data object, and at least one link connecting the function icon to the data icon. The function is arranged to perform one of disassociating a batch of data messages into individual data messages and associating data messages into a batch of data messages.