Explanation of the difference between single action, double action, and striker pistol triggers
Explanation of the difference between single action, double action, and striker pistol triggers
This article starts out as a good overview for beginners, but gets into some factual errors starting from the double-action-only section.
DAO pistols do not usually have two reset points; that's a characteristic of the SIG DAK system not found on other pistols.
As for striker-fired pistols, they can be single-action, double-action, or the intermediate design Glock popularized. Hammer-fired guns can also be intermediate with the HK LEM system being a prominent example.
I'm being a little nitpicky, but there are issues even in the single action section since the say,
One big downside is that unlike more modern revolvers, the cylinder that holds all the ammo is fixed so you can’t just swing it out and eject all the cartridges at once. You have to eject one by one…and then load one by one.
Top breaks like the Schofield eject everything all at once and many are single action. The swing out cyclinder isn't inherently part of it being double action, but is uncommon to find only one of the two features in a gun. The Colt 1877 was double action and used a typical single ejector rod.