DataAdapter更新方法 - 它使用哪个连接？

Question

对不起这个可能很愚蠢的问题.由于我在互联网上没有发现它,它可能是非常明显的,我只是盲目地看到了？!

我正在尝试通过DataAdapter.Update(数据集)从数据集更新数据库中的表

但是没有可能设置连接,DA应该使用.

DA在哪里知道如何连接到数据库？或者我是否误解了dataadapter的概念？

我目前的代码是这样的:

protected DataSet UpdateDataSet(DataSet ds)
{
   DataSet dsChanges = new DataSet();
   SqlDataAdapter da = new SqlDataAdapter();

   dsChanges = ds.GetChanges();

   //Update DataSet
   da.Update(dsChanges);

   ds.Merge(dsChanges);
   return ds;
}

我只是写了这个并且变得多可疑它是如何(或者如果)它的工作原理...我到目前为止还没有测试过它,因为我必须先编写一些其他的代码才能正确测试它

谢谢ppl,StackOVerflow FTW!

Answer 1

SqlDataAdapter需要接受一个SqlCommand对象,该对象具有绑定到它的SqlConnection对象.这几乎是层次结构崩溃的原因.

至于如何你去这样做,也有将它们传递到构造,以及设置施工后的各种属性选项.

这是一篇msdn文章,其中包含选择,插入,更新和删除的示例.

FTA:

public static SqlDataAdapter CreateCustomerAdapter(
    SqlConnection connection)
{
    SqlDataAdapter adapter = new SqlDataAdapter();

    // Create the SelectCommand.
    SqlCommand command = new SqlCommand("SELECT * FROM Customers " +
        "WHERE Country = @Country AND City = @City", connection);

    // Add the parameters for the SelectCommand.
    command.Parameters.Add("@Country", SqlDbType.NVarChar, 15);
    command.Parameters.Add("@City", SqlDbType.NVarChar, 15);

    adapter.SelectCommand = command;

    // Create the InsertCommand.
    command = new SqlCommand(
        "INSERT INTO Customers (CustomerID, CompanyName) " +
        "VALUES (@CustomerID, @CompanyName)", connection);

    // Add the parameters for the InsertCommand.
    command.Parameters.Add("@CustomerID", SqlDbType.NChar, 5, "CustomerID");
    command.Parameters.Add("@CompanyName", SqlDbType.NVarChar, 
        40, "CompanyName");

    adapter.InsertCommand = command;

    // Create the UpdateCommand.
    command = new SqlCommand(
        "UPDATE Customers SET CustomerID = @CustomerID, " + 
        "CompanyName = @CompanyName " +
        "WHERE CustomerID = @oldCustomerID", connection);

    // Add the parameters for the UpdateCommand.
    command.Parameters.Add("@CustomerID", SqlDbType.NChar, 5, "CustomerID");
    command.Parameters.Add("@CompanyName", SqlDbType.NVarChar, 
        40, "CompanyName");
    SqlParameter parameter = command.Parameters.Add(
        "@oldCustomerID", SqlDbType.NChar, 5, "CustomerID");
    parameter.SourceVersion = DataRowVersion.Original;

    adapter.UpdateCommand = command;

    // Create the DeleteCommand.
    command = new SqlCommand(
        "DELETE FROM Customers WHERE CustomerID = @CustomerID", connection);

    // Add the parameters for the DeleteCommand.
    parameter = command.Parameters.Add(
        "@CustomerID", SqlDbType.NChar, 5, "CustomerID");
    parameter.SourceVersion = DataRowVersion.Original;

    adapter.DeleteCommand = command;

    return adapter;
}