thats a catch22 question, because it completely depends on exactly what you change on the site that loaded on the subdomain. most all tweaks and adjustments are reflected in the database, unless you are hard coding to the pages. if you are hard coding to the pages, then those same changes would need to be implemented on both the subdomain and primary domain.
same with anything that gets changed that is sql related. if you make adjustments, add modules, remove blocks, add blocks upload content, this is all written to the database, the actual file upload structure is written to the database, with reference to the memberID that loaded the content, then the actual files are stored in the approrpriate folders.
i.e. audio would be uploaded, assigned to memberID then assigned an ID itself in the database, in the directory /flash/modules/mp3/files/ you will find something named i.e 1.mp3. now of course you didnt give this song the name 1.mp3 the site did, but that number is crucial to dolphin, because no other song uploaded will ever be named 1.mp3
so now 1.mp3 is associated with memberID 1 so this would be placed in your music folder.
long story short. whatever you do on the subdomain, will have to be repeated on the primary domain as far as all changes. you wont necessarily have to reload the primary domain, but replicate the changes you have made on the subdomain.
hope that sheds some light on what you are asking here.
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