How does a B-tree index work?

A B-tree (balanced search tree) is a data structure used in databases and file systems for efficient indexing and fast searching.

Principle of operation of a B-tree index:

• The tree consists of nodes, each containing multiple keys and pointers to child nodes.
• All leaves are at the same level, ensuring balance.
• Keys within a node are sorted, allowing quick access to the needed path during search.
• During index search, the algorithm compares the sought value with the keys in the node and moves to the corresponding child node.
• Insertion and deletion maintain the tree's balance so that its depth remains minimal.

Advantages:

• Minimal disk read operations, as each node corresponds to a data block.
• Fast search, insertion, and deletion in logarithmic time.

Thus, a B-tree index allows efficient retrieval of records in large data volumes, minimizing input-output operations.