1. A computer-implemented method, comprising: accessing a knowledge base stored on one or more computing devices in a computing network, the knowledge base including a plurality of entity objects and a plurality of facts, each fact corresponding to at least one of a plurality of fact types; identifying first relation data in the knowledge base corresponding to a plurality of facts of a first fact type, wherein for each fact of the first fact type in the knowledge base the first relation data express a relationship for a pair of the entity objects, and wherein for each fact of the first fact type in the knowledge base the first relation data require that one of the pair of entity objects has a unique value for a given value of the other of the pair of entity objects; identifying an entity object class based on which of the pair of entity objects corresponding to a first fact of the first fact type is unique; identifying a first subset of the entity objects that correspond to the entity object class and for which corresponding facts of the first fact type are not represented in the knowledge base; responsive to identifying the first subset of entity objects, selecting a first entity object from the first subset of entity objects for generation of a new fact of the first fact type; generating a search engine query using the first relation data and the first entity object; searching a set of documents using the search engine query to generate search results; parsing the search results to identify first information representing the first relation data for the entity corresponding to the first entity object; generating the new fact for addition to the knowledge base using the first information, the first entity object, and the first relation data; adding the new fact to the knowledge base; and repeating the selecting, generating, searching, parsing, generating, and adding for each of the entity objects included in the first subset of the entity objects.