How do I transfer data from one database to another using a DataSet?

DataTable A = load table from A
DataTable B = load table from B

foreach row in A
   col1 = row[col1]
   col2 = row[col2]
   matchRow = B.select( "col1 = " + col1 + " and col2 = " + col2)
   if not matchRow exists
      add new row to B with col1,col2
   end
end

foreach row in B
   col1 = row[col1]
   col2 = row[col2]
   matchRow = A.select( "col1 = " + col1 + " and col2 = " + col2)
   if not matchRow exists
      remove row from B
   end
end

update B