![[str_idx_btree.png|256]] - **Description**: The default and most common index type. It maintains a balanced tree structure that allows for $O(\log n)$ searches, insertions, and deletions. - **Supported Operators**: `<`, `<=`, `=`, `>=`, `>`, `BETWEEN`, `IN`, `IS NULL`, `IS NOT NULL`. - **Special Features**: - Supports anchored pattern matching (e.g., `LIKE 'foo%'`). - Can retrieve data in sorted order without an explicit sort step. - **Metaphor**: A perfectly balanced set of nested Russian dolls, where each doll tells you exactly which smaller doll to open next until you find the prize.