1. A computer-implemented method for selecting documents, comprising: under control of one or more computer systems configured with executable instructions, maintaining a dimensional model of a group of documents, the dimensional model reflecting values for a plurality of differentiated attributes for each of the documents of the group of documents, the model comprising a fact table and two or more dimension tables, the fact table comprising multiple rows each containing a document reference that references, for each attribute for which an attribute value was extracted from the document, a row corresponding to the attribute value in a dimension table of the dimensional model corresponding to the attribute; receiving a query specifying query attribute values for one or more of the plurality of attributes; and processing the query against the dimensional model to generate a query result containing a list of documents in the group of documents having the query attribute values specified by the query.