1. A method 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 method comprising: storing in the memory a plurality of functions arranged to process individual data messages or batches of data messages; retrieving from the memory a function selected from the plurality of functions; arranging on the display device a data flow diagram in response to developer input to specify a process, the data flow diagram including 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, wherein 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.