B-tree structure each node contains key values, pointers to the values, and pointers to child nodes with smaller and larger values than the value in the parent node.
in a B-Tree structure, each value is unique.
B+Tree structure： - The internal nodes only store values; they don’t store pointers to actual rows. The leaf nodes store the values and row pointers. - Leaf nodes in the B+Tree are linked
“The number of references to child pages in one page of the B-tree is called the branching factor. ” “If you want to update the value for an existing key in a B-tree, you search for the leaf page containing that key, change the value in that page, and write the page back to disk (any references to that page remain valid).”
摘录来自: Kleppmann, Martin. “Designing Data-Intensive Applications。” Apple Books.