Either way, you're going to use PHP to split up the article. Either when it's inserted (multiple records), or when it's shown (single record).
I think it'd be easier (if we're talking databases) to have an articleID, pageID, and a text column. Then store each page in a single row. There will be more people browsing the articles than there is inserting them (hopefully), so that means less code running when the people view the pages. You simple search for article=X, page=X, and retrieve the text.
This would cut the page breaking down to a single area, where you could allow the users to break it themselves, using a special code like <!--PAGE BREAK--!>, or if they don't use the code, then break it at the first period before the nth character...
I don't think searching would be affected either. Actually it may be more relevant since you can point to the exact page that the search term is on.
So, in conclusion, I vote for the multiple records idea, each record holding one page.
---John Holmes...