Someone please help me Design the database of bill of materials with 1 item can have mutiple parent

Question

I got this sample from  Uri
Dimant (MCC, MVP) ,
The problem is i want 1 item to have multiple parent  but this example don t   let 1  item to have multiple parents. this is not suit for my objective. 
CREATE TABLE Employees
  empid   int         NOT NULL,
  mgrid   int         NULL,
  empname varchar(25) NOT NULL,
  salary  money       NOT NULL,
  CONSTRAINT PK_Employees PRIMARY KEY(empid),
  CONSTRAINT FK_Employees_mgrid_empid
    FOREIGN KEY(mgrid)
    REFERENCES Employees(empid)
CREATE INDEX idx_nci_mgrid ON Employees(mgrid)
SET NOCOUNT ON
INSERT INTO Employees VALUES(1 , NULL, 'Nancy'   , $10000.00)
INSERT INTO Employees VALUES(2 , 1   , 'Andrew'  , $5000.00)
INSERT INTO Employees VALUES(3 , 1   , 'Janet'   , $5000.00)
INSERT INTO Employees VALUES(4 , 1   , 'Margaret', $5000.00) 
INSERT INTO Employees VALUES(5 , 2   , 'Steven'  , $2500.00)
INSERT INTO Employees VALUES(6 , 2   , 'Michael' , $2500.00)
INSERT INTO Employees VALUES(7 , 3   , 'Robert'  , $2500.00)
INSERT INTO Employees VALUES(8 , 3   , 'Laura'   , $2500.00)
INSERT INTO Employees VALUES(9 , 3   , 'Ann'     , $2500.00)
INSERT INTO Employees VALUES(10, 4   , 'Ina'     , $2500.00)
INSERT INTO Employees VALUES(11, 7   , 'David'   , $2000.00)
INSERT INTO Employees VALUES(12, 7   , 'Ron'     , $2000.00)
INSERT INTO Employees VALUES(13, 7   , 'Dan'     , $2000.00)
INSERT INTO Employees VALUES(14, 11  , 'James'   , $1500.00)
WITH EmpCTE(empid, empname, mgrid, lvl)
AS
  -- Anchor Member (AM)
  SELECT empid, empname, mgrid, 0
  FROM Employees
  WHERE empid = 1
  UNION ALL
  -- Recursive Member (RM)
  SELECT E.empid, E.empname, E.mgrid, M.lvl+1
  FROM Employees AS E
    JOIN EmpCTE AS M
      ON E.mgrid = M.empid
SELECT * FROM EmpCTE
My object is
I want to design the database of bill of materials which contain item and amount.
So the amount of child will depend on amount of parent in term of ratio. For example
A(1)               A(2)
|         ---->     |
B(2)               B(4)
My problem is when i try to add the parent and child . Let A is the parent of B , If i try to add A to be the child of C
I want B to come along with A as well. For example
A                       C
|     C  --->        |           For this I have to store the relation of all item in  my list to check that this item have a child or not if yes
B                            
A              The child must come along with its parent , What the Er-diagram should be for all of my requirement?
    |
    B
Base on the example that Uri
Dimant gave me ,  i have to stroe 1 item wtih multi parents for example if b is a child of a And b  have c as child , When i insert D as a parent of B   , c will automatic come along with B , But this not seem gonna work.
item   Parent 
 A      NULL
B         A
C         B
B         D
Am i wrong to go this way  , any idea

Answer 1

thanks Uri
Dimant
I am
little confuse about how can i write
hierarchy sql  from this relation  , Thanks
so far i got 
WITH EmpCTE(cid, cname, pid, lvl)
AS
  SELECT      cid , cname ,  children.pid , 0
  FROM            children INNER JOIN
  parents ON children.pid = parents.pid
  where  cid = 1
  UNION ALL
  SELECT      E.cid , E.cname ,  E.pid , M.lvl+1
  FROM       ( select  cid , cname , children.pid FROM  children INNER JOIN
  parents ON children.pid = parents.pid) AS E JOIN EmpCTE AS M
      ON E.pid = M.cid
SELECT * FROM EmpCTE