Set to the MiniVend database identifier of a table that contains Variable settings. These settings add on to but overwrite any that are set in the catalog configuration files, including any #include files.
Database variable variable.asc TAB VariableDatabase variable
Only a key and value are needed; multiple columns don't make sense, though you could include variable values in another table. In that case, append the column name to the database identifier, separated by a colon; i.e. variable:variable_setting.