Databases & Data Storage
B-Tree
Definition
A B-tree is a self-balancing tree data structure that maintains sorted data and allows searches, sequential access, insertions, and deletions in logarithmic time. The B-tree is a generalization of a binary search tree in that a node can have more than two children.
Why It Matters
B-trees are the classic and most widely used data structure for implementing database indexes. Their structure is optimized for systems that read and write large blocks of data, making them a perfect fit for disk-based storage.
Contextual Example
When you create an index on a table column, the database will typically build a B-tree data structure behind the scenes. This tree allows it to quickly navigate to the data you are looking for without scanning the whole table.
Common Misunderstandings
- B-trees are "balanced," which means they have a similar number of records in each branch, ensuring that lookups are consistently fast.
- Most modern database systems use a variant called B+ tree for their indexes.