12. The method of claim 11 wherein the unstructured data source is one of: an article, a document, a web page, an HTML file, and a spreadsheet.
11. The method of claim 1 further comprising: storing in the database an entity table that contains attributes about an unstructured data source, including a title of the unstructured data source; and establishing in the database a field-to-text link between a data item integrated from a structured data source and the entity table if the integrated data item is mentioned in the unstructured data source.