B+ Tree structure with buckets (Begginer question)
It is not mandatory for a b+tree leaf to have a pointer towards the next leaf, but it is a widely used optimization to allow efficient scanning of value ranges, such as, in the context of relational databases, supporting WHERE field BETWEEN x AND y or WHERE field &gt; x predicates. Frequently you see a leaf pointing to both next and previous leaves, supporting bidirectional scanning as well (for WHERE field &lt; x). Apart from the search predicate support, it may also be useful for record ordering and aggregation.