從結果集更新數據庫

Question

SQL語句層返回多個值，我想用所有這些值更新數據庫中的列這裏有什麼問題？

 String cust_code = session.getAttribute("Cust_Code").toString(); 
     String video_typ = session.getAttribute("video_typ").toString(); 
     int personal_p = Integer.parseInt(session.getAttribute("personal_p").toString()); 
     int layers_p = Integer.parseInt(session.getAttribute("layers_p").toString()); 
     String parent_cod = session.getAttribute("parent_code").toString(); 
     Class.forName("com.mysql.jdbc.Driver"); 
     Connection con = DriverManager.getConnection("jdbc:mysql://localhost:3306/ontube", "root", "123456"); 
     Statement st = con.createStatement(); 
     String personal_po = "update customers set personal_p =personal_p + '"+personal_p+"' where membership_num='"+cust_code+"' "; 
     String first_layer="update customers set layers_p = layers_p+'"+layers_p+"' where membership_num='"+parent_cod+"'"; 
     int pers_points = st.executeUpdate(personal_po); 
     int first_lyr = st.executeUpdate(first_layer); 
     String layers="select membership_num from customers where parent_num='"+parent_cod+"'" ; 
     // i want to update all values comes from these resultset 
     ResultSet rs = st.executeQuery(layers); 

     while(rs.next()){ 
     String names =rs.getString(1); 

     String update_layers = "update customers set layers_p = layers_p + '"+layers_p+"' where membership_num='"+names+"' "; 

     int nms = st.executeUpdate(update_layers); 

Answer 1

您應該更改這些行：

String personal_po = "update customers set personal_p =personal_p + '"+personal_p+"' where membership_num='"+cust_code+"' "; 
String first_layer="update customers set layers_p = layers_p+'"+layers_p+"' where membership_num='"+parent_cod+"'"; 
String update_layers = "update customers set layers_p = layers_p + '"+layers_p+"' where membership_num='"+names+"' "; 

更換：
...set xxxxx_p = xxxxx_p + '" + xxxxx_p + "'...與
...set xxxxx_p = '" + xxxxx_p + "'...。

UPDATE：
另外，不要使用更新相同Statement，同時還在讀書ResultSet。

... 
Statement st2 = con.createStatement(); 
while(rs.next()){ 
    ... 
    int nms = st2.executeUpdate(update_layers); 
} 
... 

Answer 2

String update_layers = "update customers set layers_p = layers_p + '" + layers_p + "' where membership_num='" + names + "' "; 

應該是：

String update_layers = "update customers set layers_p = '" + layers_p + "' where membership_num='" + names + "' ";