RM Hierarchy Management System

A hierarchical relationship management system using the Nested Set Model for efficient tree operations in MongoDB.

Problem

Managing Relationship Manager (RM) hierarchies in a fintech organization is complex:

• Multi-level hierarchies (Regional Head → City Head → RM → Sub-RM)
• Need to quickly find all clients under any RM or their descendants
• Complex reporting across organizational structures
• Traditional parent-child references required recursive queries

Solution: Nested Set Model

Instead of recursive parent-child references, I implemented the Nested Set Model which represents tree structures using left/right boundary values:

How It Works

// Each node has left and right values
// A node's descendants have left > node.left AND right < node.right
{
  "name": "Regional Head",
  "left": 1,
  "right": 14,
  "depth": 0
}
// City Head 1: left=2, right=7
// City Head 2: left=8, right=13

Key Operations

• Find all descendants: left > node.left AND right < node.right — O(1) query!
• Find ancestors: left < node.left AND right > node.right
• Count descendants: (right - left - 1) / 2

Benefits Over Recursive Queries

• 40% faster reads for hierarchy traversal
• Single query for any tree operation
• Efficient reporting across organizational structures
• No recursive functions needed in application code

Architecture

• MongoDB with compound indexes on [left, right] for fast range queries
• Express.js API with CRUD operations that maintain left/right values
• Batch updates for tree modifications to maintain consistency
• Caching layer with Redis for frequently accessed hierarchy data

Results

• 40% performance improvement in hierarchy reads
• Simplified codebase — no recursive query functions
• Scalable to thousands of RM nodes with consistent performance