A computer-implemented method can comprise establishing programmatic connections to a digitally stored first database comprising over one million records, each of the records comprising columns; reading a configuration file that specifies tables in the database; for each particular table, forming and submitting a plurality of queries to the database, each of the queries specifying data aggregation operations, and in response thereto, receiving result sets of records of the database; calculating metadata metrics that characterize columns of the records in the result sets and storing the metadata metrics in tables for string column statistics, numeric column statistics, date column statistics, based upon a particular data type among different data types of the columns; generating presentation instructions which when rendered cause displaying one or more graphical visualizations in a graphical user interface.