Common data model including field interdependencies

There are situations where data exists in multiple data stores, each having its own Application Programming Interface (API), which is a set of functions available for the programmer to use to program applications, and where is it desired to have its generic view of the data from the diverse stores. A typical example of the situation arises in the field of telephony, where the underlying data stores contain telephony information, such as telephone numbers, hunt groups, and the like. A method is disclosed for managing data from a variety of sources, where each source provides its own API (Application Programming Interface). A data management layer containing metadata describes entities in each source by collating the metadata and presenting it in generic form. An upper level view controller communicates with the data management layer to manage the data from the different sources.