When and why is it advisable to use a B-tree for storing data in a database?

A B-tree is appropriate for storing data in a database when efficient search, insertion, and deletion of data are required with minimal disk input/output operations.

Reasons to use a B-tree:

• Balancing: B-tree is always balanced, which guarantees logarithmic access time.
• Optimization for disk operations: Unlike binary trees, B-tree stores multiple keys in a single node, reducing the number of disk reads.
• Support for range queries: B-tree is well-suited for range-based queries.

It is used in database indexes where high performance is important when working with large volumes of data on external storage.

Example: In a DBMS, an index on a table field is implemented using a B-tree, which allows for quick record retrieval by key and efficient index updates upon changes.