Indexing on string URLs. How efficient ?

What is the best way to store permalinks/slugs when you have the parent-child model like Radiant? In radiant each page can have many child pages and each page has slug which is unique in the scope of parent. Now, every time a create request is made. it finds all associated ancestor pages and there children.

Eg.:
If the request is http://mysite.com/a/b/c/d/e/f , it will find all the pages from a-f(around 12 queries for finding the page and finding its children), which is quite unnecessary if you store “a/b/c/d/e/f” itself in the slug. Actually, I have a pretty big table. Is it efficient to store this complete url and index it and search in table on the basis of this slug rather than querying for all the parent pages/other-entities ??