One interview question a day the difference between B tree and b+ tree

Basics

B Tree is also called balanced multi-path search tree , As the name suggests, this kind of data structure is generally used to search faster ,B+ Trees are B A strengthening tree of trees .

difference

B Each node of the tree stores key and data.
B Trees because of key and data The same node exists , Unable to perform interval query .
B The best time complexity of tree query is O(1）.
B+ The query time complexity of the tree is fixed as logN.
B+ Trees store data only in leaf nodes .
B+ The tree can be used for interval query , And because the non leaf node has no storage data, So each page loads more information into memory .

Extension

From the above differences, we can see why the data structure of the index in the database uses B+ Trees , The first point is that its non leaf nodes do not store data ; The second point is that you can perform interval queries ; Third, the query time complexity is fixed .