sql queries to rdbms

Hi there
I would like to create realtion database for an application .I have uploaded the screenshot of a similar application here.
http://rganesh.t35.com/
please have a look at the screen shot
look for the alternate path ,primary paths ,non primary paths option at the bottom .The first one shows the routing schedule for each parts and the second one shows the primary path and alternat part for the path 90-b091x-500.It may include sum subparts 87-B091x-50E_ADB shown in the second one

give me an idea to start with ,using the above screenshot how to create the database with tables and structures so that the queries could run faster and effective
give me the sql queries that i should be using to create such a relational database


refer to the second document tree.doc in the link http://rganesh.t35.com .In that if i want to retrieve the parent node I will do something like this
SELECT *
FROM [table]
WHERE NOT EXISTS
(SELECT * FROM structure WHERE structure.childId=[table].keyid)
but how about retreving an element named C.In the front end when u click on c it shud display c,d,e(since they are the child process of c). how can i write the sql query for that .please reply asap


thanks
ganesh