How to make hierarchical structure for the table

I have a table with below fields and data

DocNo		TransmittalNo	TransmittaltoCon
Doc-0001		tt-0002			con-0005
Doc-0005		tt-0002			con-0003
Doc-0001		tt-0002			con-0007

Now I like to make a treeview with 3 level of information of my table that level 1 is (Doc No) level 2 is (Transmittal No) and level 3 is (TransmittaltoCon) , after searching in google I read I have to make another table (query) with parent and position field for example

ID	PARENT		POSITION	    OPTION
1	0		0		    DOC-0001
2	1		0		    TT-0002
3	0		1		    DOC-0005
4	1		1		    CON-0007
5	3		0		    TT-0002
6	5         	0		    CON-0003