One of the most practical models available in SQL Server to represent trees and hierarchies, such as an Employees hierarchy, is known as the enumerated path model. In this model you add two attributes to the table. One attribute holds an enumerated path of all node IDs leading to the current node, and another attribute holds the level, or distance, from the root node. To implement this model, you can create your own custom solution in any version of SQL Server, or you can use the built-in HI...