1. A method of managing data in a data system, comprising: executing by a Service Delivery Platform (SDP) a data management tool comprising an access layer providing an Application Program Interface (API) to one or more data management functions of the data management tool and a virtual directory layer providing a virtual directory representing a unified view of customer data related to a user of a service from each of a plurality of data repositories, each data repository within a different service domain of a plurality of service domains, each service domain controlled by at least one of a plurality of different data systems, wherein the customer data of each service domain comprises identity information for the user and information related to usage of the service of that domain by the user, wherein an identity of the user is different in each service domain, wherein the virtual directory federates the different identities of the user in the different domains by mapping the different identities to a unified identifier, and wherein the API of the virtual directory provides a single interface to the customer data from the plurality of service domains using the unified identifier; receiving at the SDP a request from an application to update target customer data represented in the virtual directory and using the unified identifier, the target customer data being owned by one of the data systems and the request comprising a request from the application made through the API of the data management tool in a protocol of the API; and launching by the SDP a business process in response to receiving the request, the business process being programmed to trigger at least one condition or action, or combination thereof, needed to update the target customer data represented in the virtual directory and related customer data in the plurality of service domains through the single interface of the virtual directory as a result of the request.