how can i link category and subcategory table?

Question

I have a category page where in i have 3 columns

id

cname

cimage

I have a subcategory page where in i have 4 columns.

id

sname

simage

description

In my subcategory page , i have dropdown list in which i populate cname from the category page.  

later i have binded dynamically the cname,sname,simage,desc into gridview in the same subcategory page.

I have a problem displaying selected cname field which i have selected from dropdown in subcategory page in the gridview.

How i should link category and subcategory table so that i can perform edit delete oerations in my gridview.

plz suggest me what to do..