1. A method comprising: extracting column metadata from a relational database, the column metadata describing a plurality of columns of a data table included in the relational database, the data table comprising a plurality of data records, wherein the column metadata comprises at least one of field data types, mandatory fields, or relationships to other columns; generating a graphical mapping interface comprising an interface form and the plurality of columns of the data table, the interface form comprising a plurality of input controls; receiving, in the graphical mapping interface, user inputs defining a plurality of control-column mappings between the plurality of input controls of the interface form and the plurality of columns of the data table; in response to a receipt of the user inputs defining the plurality of control-column mappings: automatically generating, using the plurality of control-column mappings, a plurality of control-metadata mappings between the plurality of input controls to the column metadata; and using the plurality of control-metadata mappings, automatically generating, by a processor, new test data values for testing the plurality of input controls, the new test data values comprising data values that are illegal according to the column metadata.