No, there are no changes to the underlying structure of the database.
You already know what a site is (essentially, a collection of pages and entitites): well, a site is internally a "group" (in other words, a site is a "specialization" of a group), and every group has its own row in the Group_
table, where the primary key is the column groupId
. If you already built some Liferay plugins, I'm sure you already know what I'm talking about :-)
Well, when you activate staging for a site, a new group gets created: the "clone of the site" is just a new group with a special meaning (sorry if I'm oversimplifying!). Pages and entities are then copied from the original site through a LAR export/import process. This means that rows in the entities' tables (BlogsEntry
, BookmarksEntry
, DLFileEntry
and so on) will be duplicated as well, and these new rows will point to the new group: they will have the new groupId as their value for the column groupId
.
The two groups ("live" and "staging") are separated, and when you publish the staging site, its content is exported in a LAR file and then imported back in the live site.
Hope it's useful, tell me if you need some more info :-)