While preparing to shoot a GPS approach to N79; the pilot of a Socato Trinidad equipped with a Garmin GNS530W discovered the two RNAV approaches to the airport had not been included in the latest database update; notwithstanding the fact the associated aero charts had been issued by that same commercial supplier for the current revision cycle.

Narrative

When selecting the approach procedures for N79 (Shamokin; PA) on my Garmin GNS 530W; the two GPS approaches that are listed by the FAA as being in the current cycle (RNAV (GPS) Runway 08 or RNAV (GPS) Runway 26) were not in the GPS database and hence were unavailable to me. They appeared on the FAA/NACO charts and were listed on the various flight planning websites; but of course without them in the GPS database I could not fly them even with the plates. Fortunately; the weather on arrival permitted a visual approach.I contacted the commercial chart/database provider who; in an email reply; said they had omitted the approaches for N79 and some other airports; because the high volume of changes they received for that cycle (2011 Aug 25 - 2011 Sep 22) did not allow them to process them all. In an earlier phone conversation I asked them how a customer was to know that approaches had been omitted and they told me they had issued an 'alert' about the missing approaches; but I have not been able to find one. Notably; they did not say that this would not happen again. They only apologized for any inconvenience it may have caused.Current IFR procedures only require that a pilot check to see that the current database cycle is installed in the GPS; not that it contains all he approaches he is planning to use and; as a practical matter; that can't be done during flight planning anyway.At a minimum; [the database provider] should alert its database users when they omit approaches from a cycle that should be there.