1. A method for enforcing context model based Service-Oriented Architecture (SOA) policies, comprising: gathering, via a policy engine device, instance documents related to policy enforcement according to a business requirement, where the instance documents are instantiated from corresponding schema documents; generating an instantiated context model comprising references to the gathered instance documents from a context model definition; generating a policy set to be enforced via the instantiated context model according to the gathered instance documents; determining an enforcement sequence of policies in the policy set; applying the policies to the instantiated context model according to the enforcement sequence; and providing context model-based forward chaining, comprising: determining whether the instantiated context model should be updated; if the instantiated context model should be updated: updating the instantiated context model with at least one updated instance document comprising: executing an updating operation to create the at least one updated instance document; detecting and resolving a conflict caused by the updating operation; generating the updated instantiated context model according to the at least one updated instance document and the instantiated context model; and re-applying the policies to only the at least one updated instance document within the updated instantiated context model according to the enforcement sequence.