ALTER TABLE T1
ADD CONSTRAINT FK_T1_this_Id FOREIGN KEY (this_Id) REFERENCES T1 (root_Id)

CREATE TABLE Tree(
  ID            int IDENTITY( 1 ,  1 ) NOT NULL,
  ParentID      int NULL,

  CONSTRAINT PK_Tree PRIMARY KEY CLUSTERED (ID),
  CONSTRAINT FK_Tree_ParentID FOREIGN KEY (ParentID) REFERENCES Tree (ID)
)

CREATE TABLE TreeNodes(
  ID            int IDENTITY( 1 ,  1 ) NOT NULL,
  ParentID      int NULL,

  CONSTRAINT PK_TreeNodes PRIMARY KEY CLUSTERED (ID),
  CONSTRAINT FK_TreeNodes_ParentID FOREIGN KEY (ParentID) REFERENCES TreeNodes (ID)
)

CREATE TABLE NodeData(
  ID            int IDENTITY( 1 ,  1 ) NOT NULL,
  TreeNodeID    int NOT NULL CONSTRAINT CHK_NodeData_TreeNodeID CHECK (dbo.fn_NodeIsValid(TreeNodeID) =  1 ),

  CONSTRAINT PK_NodeData PRIMARY KEY CLUSTERED (ID),
  CONSTRAINT FK_NodeData_TreeNodeID FOREIGN KEY (TreeNodeID) REFERENCES TreeNodes (ID)
)

CREATE FUNCTION dbo.fn_NodeIsValid (@HandbookID int, @id int)
RETURNS int
AS
BEGIN
  RETURN 
    CASE @HandbookID
      WHEN  1  THEN CASE WHEN EXISTS(SELECT * FROM TreeNodes1 WHERE ParendID = @Id) 
			                 THEN  1  ELSE  0  
                  END
      WHEN  2  THEN CASE WHEN EXISTS(SELECT * FROM TreeNodes2 WHERE ParendID = @Id) 
			                 THEN  1  ELSE  0  
                  END
      ...
    END
END