1. A product management system employing rules to drive integration, the system comprising: a processor in communication with memory; a core workflow manager in communication with the processor, wherein the core workflow manager operates a core workflow at a management level, and wherein the core workflow includes a common set of workflows that automate common processes in an enterprise; at least one integration adapter in communication with the core workflow manager; an integration rule manager to establish one or more model rules wherein at least one model rule defines at least one condition under which the at least one integration adapter is to be invoked; the processor to compare a condition at run-time to the one or more model rules, filter the one or more model rules meeting the at least one defined condition, and establish a relationship between the at least one integration adapter and a workflow step; and an integration manager in communication with the processor, the integration manager to select at least one integration adapter to be invoked when the core workflow is executed, wherein the at least one invoked integration adapter is configured to: transform data associated with the workflow step to a format of a target application of an external system; and integrate the transformed data with the external system while the functionality in the core workflow remains constant.