internal/protocol/parameter.go
func (f *ParameterField) TypePrecisionScale() (int64, int64, bool) {
	if f.tc.isDecimalType() {
		return int64(f.length), int64(f.fraction), true
	}
	return 0, 0, false
}
func (f *ParameterField) TypePrecisionScale() (int64, int64, bool) {
	if f.tc.isDecimalType() {
		return int64(f.length), int64(f.fraction), true
	}
	return 0, 0, false
}
// TypePrecisionScale returns the type precision and scale (decimal types) of the field.
// see https://golang.org/pkg/database/sql/driver/#RowsColumnTypePrecisionScale