As mentioned in my previous post about another patch for do_jdbc we heavily use DataMapper. Another bug we found in do_jdbc is in the method setParameterStatementParam. It is responsible for filling the parameters of a PreparedStatement with their values. At this point, it is necessary to convert ruby values into java values. In case of a Fixnum the ruby value is parsed as an Integer, which could be too small to hold a large Fixnum value. The patch for this problem is quite simple. Have a look at our github repository containing the patch. The patch was already pulled into the next branch of the official project and will hopefully make it into the next release.