Why don't calcium chloride and sodium nitrate react? $$\ce{CaCl2 + 2NaNO3 -&gt; 2NaCl + Ca(NO3)2}$$

Why doesn't the above reaction occur? Does it have to do with the metal activity series or solubility rules?
It's because all the species are soluble in water and there is no driving force such as precipitation or gas evolution. You just have a mixture of ions.