Let us see how to delete the database using DBCA tool?

S-1: choose delete database => Press " Next "  

D1

S-2: choose the database name  => Press " Next "  

D2  

S-3: Press "Yes"

D3  

S-4: Press "Ok"

D4    

S-5: Once database  has been deleted it ll ask whether you want to do any other operation  if you press "Yes" dbca tool can continue or press  "No" tool exist  

  D6