从包含多个表的数据集更新数据库

Question

这是我的代码：

public partial class Form1 : Form
{
    SqlDataAdapter da = new SqlDataAdapter();
    SqlConnection cn;
    SqlCommand selectcommand;
    DataSet ds = new DataSet();
    List<Customer> customers = new List<Customer>();

    public Form1()
    {
        InitializeComponent();
        cn = new SqlConnection(Properties.Settings.Default.exsisDBConnectionString);
    }

    private void Form1_Load(object sender, EventArgs e)
    {
        System.Threading.TimerCallback callback = new System.Threading.TimerCallback(ProcessTimerEvent);

        var dt = new DateTime(DateTime.Now.Year, DateTime.Now.Month, DateTime.Now.Day, 10, 5, 0);

        if (DateTime.Now < dt)
        {
            var timer = new System.Threading.Timer(callback, null, dt - DateTime.Now, TimeSpan.FromHours(24));
        }
    }

    private void ProcessTimerEvent(object obj)
    {
        cn.Open();
        selectcommand = new SqlCommand("SELECT * FROM Customer; SELECT * FROM [Transaction]; SELECT * FROM Notification; SELECT * FROM NotificationLink; SELECT * FROM Product; SELECT * FROM TransactionItem", cn);
        da.SelectCommand = selectcommand;
        da.TableMappings.Add("Table", "Customer");
        da.TableMappings.Add("Table1", "Transaction");
        da.TableMappings.Add("Table2", "Notification");
        da.TableMappings.Add("Table3", "NotificationLink");
        da.TableMappings.Add("Table4", "Product");
        da.TableMappings.Add("Table5", "TransactionItem");
        da.Fill(ds);

        customers.Clear();
        foreach (DataRow row in ds.Tables["Customer"].Rows)
        {
            Customer customer = new Customer();
            customer.CustID = row["CustID"].ToString();
            customer.RepID = row["RepID"].ToString();
            List<Transaction> customerTransactions = new List<Transaction>();
            foreach (DataRow row2 in ds.Tables["Transaction"].Rows)
            {
                if (row2["CustID"].ToString() == customer.CustID)
                {
                    Transaction transaction = new Transaction();
                    transaction.DocNo = row2["DocNo"].ToString();
                    transaction.Date = Convert.ToDateTime(row2["Date"]);
                    customerTransactions.Add(transaction);
                }
            }
            customer.Transactions = customerTransactions;
            customers.Add(customer);
        }

        LastOrder();

        cn.Close();
    }

    private void LastOrder()
    {
        foreach (Customer customer in customers)
        {
            DateTime LastOrderDate = Convert.ToDateTime(customer.Transactions.Last().Date);
            TimeSpan TimeSinceLastOrder = DateTime.Now - LastOrderDate;

            if (TimeSinceLastOrder.TotalDays > 30)
            {
                DataRow row = ds.Tables["Notification"].NewRow();
                row["CustID"] = customer.CustID;
                row["DateGenerated"] = Convert.ToString(DateTime.Now);
                row["NotificationType"] = "Last Order";
                if (ds.Tables["Notification"].Rows.Count == 0)
                {
                    row["NotificationID"] = "1";
                }
                else
                {
                    DataRow nid = (DataRow)ds.Tables["Notification"].Rows[ds.Tables["Notification"].Rows.Count - 1];
                    row["NotificationID"] = Convert.ToString(Convert.ToInt32(nid["NotificationID"]) + 1);
                }
                row["DocNo"] = customer.Transactions.Last().DocNo;
                ds.Tables["Notification"].Rows.Add(row);

                DataRow row2 = ds.Tables["NotificationLink"].NewRow();
                if (ds.Tables["NotificationLink"].Rows.Count == 0)
                {
                    row2["NotificationLinkID"] = "1";
                }
                else
                {
                    DataRow nlid = (DataRow)ds.Tables["NotificationLink"].Rows[ds.Tables["NotificationLink"].Rows.Count - 1];
                    row2["NotificationLinkID"] = Convert.ToString(Convert.ToInt32(nlid["NotificationLinkID"]) + 1);
                }
                row2["NotificationID"] = row["NotificationID"];
                row2["RepID"] = customer.RepID;
                ds.Tables["NotificationLink"].Rows.Add(row2);
            }
        }
        da.Update(ds);
    }
}

当我运行它时，我没有收到任何错误，但是在运行之后数据库还没有更新。我很确定这个问题与我缺少一个InsertCommand有关，但是当我使用像这样的多个表时，我不确定如何构造一个InsertCommand。

我尝试了一下SqlCommandBuilder。我没有运气，虽然我真的不明白SqlCommandBuilder是如何工作的，所以我可能会遗漏一些东西。

另外，作为旁注，当谈到将文本添加到InsertCommand时，是否仍然要跳过添加值并让它使用您为新DataRow分配的值？因为将值分配给DataRow然后再将其分配给SQL语句似乎有点多余。