Abstract: A method and system for entities of a data access layer, the data access layer following an entity-relationship model in which data are depicted in term of entities and relationships between them and the entities are provided with a CRUD interface. The method includes the steps of: defining a meta-entity being a virtual entity, resulting as a composition of parts of one or more entities; describing the virtual entity, via a virtual entity descriptor, as a hierarchical structure in which entities are connected in a parent-child structure via a link; in the virtual entity descriptor, specifying which properties are taken from each entity to form partial entities of the virtual entity; providing a CRUD interface on the virtual entity; and at run time, accessing the virtual entity via its CRUD interface. The accessing is implemented as a set of calls to CRUD methods accessing the entities composing the virtual entity.