1. A method for transforming web service policies from a logical model to a physical model, wherein the logical model comprises a plurality of logical service components and logical dependency relationships among the plurality of logical service components, at least one of the plurality of logical service components being specified with logical policies, the physical model comprises physical components and physical dependency relationships associated with the plurality of service components and logical dependency relationships among the plurality of service components in the logical model, the method comprising: calculating effective logical policies for each of the plurality of logical service components in said logical model; and mapping each effective logical policy of each logical service component in said logical model to at least one associated physical component in said physical model; wherein said logical model further comprises a system to which at least one of said plurality of logical service components belongs and which has been specified with logical policies, and wherein calculating the effective logical policies for each of the plurality of logical service components in said logical model further comprises, for each logical service component in said system, taking the AND set of its logical policies and the logical policies of the system as the effective logical policies of the service component.