I tend to roll-my-own when it comes to Hierarchies.

Here's how I do it.

Say I have a list of Employees with a Key on ID

I then make a Employee_Hierarchy table then an Employee_SuperHierarchy table

Employee_Hierarchy contains the parent and child Employee Primary Keys and is a compound unique index.

Employee_SuperHierarchy contains the parent and child Employee Primary key and the Gap.

For every Employee row there's an Row in with Gap=0

It contains the expanded hierarchy so if (A) is the boss of (B) and (B) is the boss of (C) then

A, A, 0

B, B, 0

C, C, 0

A, B, 1

B, C, 1

A, C, 2

You can then loop until no more are inserted to build the full hierarchy by

INSERT INTO Employee_SuperHierarchy

(Parent, Child, Gap)

SELECT Parent.ParentID

, Child.ChildID

, Child.Gap + 1

FROM Employee_SuperHierarchy Child

INNER JOIN Employee_Hierarchy Parent

ON Child.ParentID = Parent.ChildID

Then you can easily run a query to find all the employees (or Bosses) of a person. Do make sure to exclude Gap = 0 (employs self/Self boss)

E.g. To find all the employees

SELECT Employee.*

FROM Employee Boss

INNER JOIN Employee_SuperHierarchy

ON Employee_SuperHierarchy.ParentID = Boss.ID

INNER JOIN Employee

ON Employee.ID = Employee_SuperHierarchy.ChildID

WHERE Boss.Name = 'Stalin'