An apparatus, computer-readable medium, and computer-implemented method for extracting a subset, including receiving a request comprising one or more criteria indicating one or more criteria tables in a plurality of tables of the database, storing an entity graph corresponding to a schema of the database and the one or more criteria, determining one or more top-most criteria entities in the entity graph, and generating the subset from the plurality of tables by traversing the entity graph starting at the one or more top-most criteria entities without traversing any directed edge more than once.