First you need to check your connection if it is working fine. Than come to DSV right click on DSV Designe area than select add/remove table option. On top of the prompt check your datasource is select or not, if not select it then add table which you want to add in DSV, If there is no relation ship appeared, No Problem you just drag n drop column from one table to other to create relationship. If you want to check your relation is properlly define or not, select arrow than right click and select edit relation.
Please check & reply me.. it work for you or not. :-)