13. A computer program product for supplementing structured information within a data system for entities based on unstructured data comprising: a non-transitory computer readable storage medium having computer readable program code embodied therewith, the computer readable program code comprising computer readable program code configured to: analyze one or more documents with unstructured data pertaining to the entities of the structured information and identify from the unstructured data one or more relationships between the entities of the structured information; extract attribute values from the unstructured data for one or more of the entities of the structured information, wherein extracting attribute values from the unstructured data includes: extracting attribute values based on a comparison of the unstructured data with one or more dictionaries each including values for a corresponding attribute of an entity within the data system; retrieve entity records with structured information from the data system based on the extracted attribute values; construct entity references for corresponding one or more of the entities of the data system based on a comparison of the retrieved entity records and the extracted attribute values; link the entity references to the corresponding one or more entities within the data system, wherein the entity references include extracted attributes from the unstructured data for corresponding linked entities, and wherein linking the entity references includes: inserting the entity references into one of the data system and an external data source based on a comparison of matching scores for the entity references with corresponding thresholds; define new relationships in the data system between the entities within the structured information corresponding to the one or more relationships between the entities identified from the unstructured data; create the new defined relationships between the entities in the data system by linking the entities of the structured information to each other within the structured information based on the one or more relationships between those entities identified within the unstructured data; and process a query for the data system to retrieve at least one entity of the structured information including the entities linked to the at least one entity based on the defined new relationships and the corresponding unstructured data of the linked entity references.
16. The computer program product of claim 13 , wherein an attribute of an entity includes a plurality of atomic attributes, and extracting attribute values from the unstructured data includes: extracting attribute values for each of the individual atomic attributes from the unstructured data.