What data structure serves as the basis for implementing tree-based indexing in databases?

The basis for implementing indexing as a tree in databases is the data structure B-tree or its variations, such as B+-tree.

A B-tree is a balanced search tree optimized for working with large volumes of data and storage on disk. It allows efficient execution of search, insert, and delete operations with minimal disk access.

An example of using a B-tree:

• Indexes in relational databases (such as MySQL, PostgreSQL) are often implemented based on B+-trees.

In Python, for demonstration, you can use third-party libraries that implement B-trees or write a simplified structure, but in real databases, this is implemented at the C/C++ level.