Editing B+ tree (section)

===Bulk-loading===
Given a collection of data records, we want to create a B+ tree index on some key field. One approach is to insert each record into an empty tree. However, it is quite expensive, because each entry requires us to start from the root and go down to the appropriate leaf page. An efficient alternative is to use bulk-loading.
* The first step is to sort the data entries according to a search key in ascending order.
* We allocate an empty page to serve as the root, and insert a pointer to the first page of entries into it.
* When the root is full, we split the root, and create a new root page.
* Keep inserting entries to the right most index page just above the leaf level, until all entries are indexed.

Note:
* when the right-most index page above the leaf level fills up, it is split;
* this action may, in turn, cause a split of the right-most index page one step closer to the root;
* splits only occur on the right-most path from the root to the leaf level.<ref>{{Cite web|url=http://web.cs.ucdavis.edu/~green/courses/ecs165b-s10/Lecture6.pdf|title=ECS 165B: Database System Implementation Lecture 6|date=April 9, 2010|website=UC Davis CS department|pages=21–23}}</ref>