Method, system, and programs for providing identifiers to objects. Input data representing a plurality of objects is received and categorized into a plurality of entity categories. A first graph of entities is generated using the plurality of entity categories. The first graph of entities are matched with a second graph of entities. A comparison of object pairs is then made, in which each object pair includes a first object from the first graph of entities and a corresponding second object from the second graph of entities. Identifiers are assigned to each object based on comparing the object pairs.