According to the following part of the QSQL documentation points out http://doc.qt.nokia.com/4.8-snapshot/qsql.html#NumericalPrecisionPolicy-enum default numerical precision policy value should be 0 (QSql::HighPrecision). But as the attached sample code shows and following code snippet from the qt code it is set to 4 (QSql::LowPrecisionDouble). So the documentation should be updated accordingly.