使用详细信息表中的外键将数据从C＃插入到SQL Server 2005中的主/明细表中

Question

I need some help to make a order form in C#. My development environment is:

• Microsoft Visual Studio 2010 Ultimate
• SQL Server Express Edition 2005
• Programming Language C#
• Sample Database = NorthWind (Tables Orders and OrderDetails )

I've create a form for order entry, which contain a textbox for OrderID , a combobox for Customer , DateTimePickers for OrderDate and ShippedDate and a DataGridView which contains columns OrderID (readonly) , ProductID , UnitPrice & Quantity .

In the form load event I've the following code:

private void Inv2_Load(object sender, EventArgs e)
{
        SetComb();
        connectionString = ConfigurationManager.AppSettings["connectionString"];
        sqlConnection = new SqlConnection(connectionString);

        qryOrd = "Select OrderID, CustomerID, OrderDate, ShippedDate from Orders";
        qryOrdDet = "Select OrderID, ProductID, UnitPrice, Quantity from OrderDetails";

        sqlConnection.Open();
        sqlDataMaster = new SqlDataAdapter(qryOrd, sqlConnection);
        sqlDataDet = new SqlDataAdapter(qryOrdDet, sqlConnection);

        //SET MASTER INSERT/UPDATES
        command = new SqlCommand("INSERT INTO Orders ( CustomerID, OrderDate, ShippedDate) VALUES (@CustID, @OrdDt, @ShipDt) SELECT SCOPE_IDENTITY();");

        command.Parameters.Add("@OrdID", SqlDbType.NVarChar, 15);
        command.Parameters.Add("@CustID", SqlDbType.VarChar, 15);
        command.Parameters["@CustID"].Value = cmbCust.SelectedText;

        command.Parameters.Add("@OrdDt", SqlDbType.DateTime);
        command.Parameters["@OrdDt"].Value = dtOrdDt.Text;

        command.Parameters.Add("@ShipDt", SqlDbType.DateTime);
        command.Parameters["@ShipDt"].Value =dtShipDt.Text;

        sqlDataMaster.InsertCommand = command;
        //string id = command.ExecuteScalar().ToString();

        command = new SqlCommand("UPDATE Orders SET CustomerID = @CustID, OrderDate = @OrdDt, ShippedDate = @ShipDt WHERE OrderID = @OrdID");

        command.Parameters.Add("@OrdID", SqlDbType.NVarChar, 15, "OrderID").Value = txtOrdID.Text; 
        command.Parameters.Add("@CustID", SqlDbType.VarChar, 15, "CustomerID").Value = cmbCust.Text;
        command.Parameters.Add("@OrdDt", SqlDbType.DateTime).Value = dtOrdDt.Text;
        command.Parameters.Add("@ShipDt", SqlDbType.DateTime).Value = dtShipDt.Text;
        sqlDataMaster.UpdateCommand = command;

        //SET DETAILS INSERT/UPDATES
        commandDet = new SqlCommand("INSERT INTO OrderDetails (ProductID, UnitPrice, Quantity) VALUES (@PrdID, @Up,@Qty)");

        //commandDet.Parameters.Add("@OrdID", SqlDbType.NVarChar, 15, "OrderID").Value = txtOrdID.Text; ;  
        commandDet.Parameters.Add("@PrdId", SqlDbType.NVarChar, 5, "ProductID");
        commandDet.Parameters.Add("@Up", SqlDbType.VarChar, 50, "UnitPrice");
        commandDet.Parameters.Add("@Qty", SqlDbType.VarChar, 20, "Quantity");
        sqlDataDet.InsertCommand = commandDet;

        commandDet = new SqlCommand("UPDATE OrderDetails SET ProductID = @PrdID, UnitPrice = @Up, Quantity = @Qty WHERE OrderID = @OrdID");
        commandDet.Parameters.Add("@OrdID", SqlDbType.NVarChar, 15, "OrderID").Value = txtOrdID.Text; ;  
        commandDet.Parameters.Add("@PrdId", SqlDbType.NVarChar, 5, "ProductID");
        commandDet.Parameters.Add("@Up", SqlDbType.VarChar, 50, "UnitPrice");
        commandDet.Parameters.Add("@Qty", SqlDbType.VarChar, 20, "Quantity");
        sqlDataDet.UpdateCommand = commandDet;

        sqlComBldMaster = new SqlCommandBuilder(sqlDataMaster);
        sqlComBldDet = new SqlCommandBuilder(sqlDataDet);

        dt = new DataTable();
        dtDet = new DataTable();

        dt.Clear();
        dtDet.Clear();

        sqlDataMaster.FillSchema(dt, SchemaType.Source);
        sqlDataDet.FillSchema(dtDet, SchemaType.Source);

        dtDet.Columns["OrderID"].AutoIncrement = true;
        dtDet.Columns["OrderID"].AutoIncrementSeed = -1;
        dtDet.Columns["OrderID"].AutoIncrementStep = -1;
        ds = new DataSet();
        ds.Tables.Add(dt);
        ds.Tables.Add(dtDet);
        ds.EnforceConstraints = false;

        DataRelation rel = new DataRelation("OrdersRel", ds.Tables["Orders"].Columns["OrderID"], ds.Tables["OrderDetails"].Columns["OrderID"]);
        ds.Relations.Add(rel);

        bs = new BindingSource();
        bsDet = new BindingSource();

        bs.DataSource = ds;
        bs.DataMember = "Orders";

        bsDet.DataSource = ds;
        bsDet.DataMember = "OrderDetails";

        dgInvDet.AutoGenerateColumns = false;

        dgInvDet.Columns["ProductID"].DataPropertyName = "ProductID";
        ProductID.DataSource = dm.GetData("Select * from Products order by ProductName");
        ProductID.DisplayMember = "ProductName";
        ProductID.ValueMember = "ProductID";
        dgInvDet.Columns["UnitPrice"].DataPropertyName = "UnitPrice";
        dgInvDet.Columns["Quantity"].DataPropertyName = "Quantity";   

        dgInvDet.DataSource = bsDet;
    }

public void SetComb()
{
        cmbCust.DataSource = dm.GetData("Select * from Customers order by CompanyName");
        cmbCust.DisplayMember = "CompanyName";
        cmbCust.ValueMember = "CustomerId";
        cmbCust.Text = "";
}

Dm.GetData is the data access class method created for the purpose of just retrieving rows...

And in the Save button click event:

 private void btnSave_Click(object sender, EventArgs e)
 {
     dt.EndInit();

     rec = sqlDataMaster.Update(ds.Tables[0]);
     rec += sqlDataDet.Update(ds.Tables[1]);
     //recDet = sqlDataDet.Update(dt);

     ds.AcceptChanges();            

     MessageBox.Show(rec + " record(s) applied...." );

     ds.EnforceConstraints = true;
}

What I need is to save the data to SQL Server in respective table ( Orders and OrderDetails ) which my code can't seem to do. It shows an error that foreign key cannot be null... because OrderDetails table also needs OrderID which is foreign key, and I am unable to understand how can I get the OrderID , as it is auto-generated after data is inserted into database.

Please help me on this problem to save the data in database with this foreign key issue...

Any help will be much appreciated.

Thanks

Ahmed

Answer 1

I can think of a couple options here. First, you could modify your SQL on your master data adapter to perform the insert on both the order and order details tables at the same time (same goes for the update) and wrap them in a transaction (of course do the same on the updates...).

Another option would be to handle the RowUpdated event (since it will fire on insert) of the data adapter, grab the ID, and then update the detail.

Here is a brief example of what I was talking about in the first solution:

sqlDataMaster = new SqlDataAdapter(qryOrd, sqlConnection);
sqlDataDet = new SqlDataAdapter(qryOrdDet, sqlConnection);

//SET MASTER INSERT/UPDATES

command = new SqlCommand("DECLARE @tempOrderId numeric(38,0);" +
                            "BEGIN TRAN;" + 
                            "INSERT INTO Orders ( CustomerID, OrderDate, ShippedDate) VALUES (@CustID, @OrdDt, @ShipDt);" + 
                            "SELECT @tempOrderId = SCOPE_IDENTITY();" + 
                            "INSERT INTO OrderDetails (OrderId, ProductID, UnitPrice, Quantity) VALUES (@tempOrderId, @PrdID, @Up,@Qty);"
                            "IF @@Error <> 0 " + 
                            "   ROLLBACK TRANS" + 
                            "ELSE " + 
                            "   COMMIT TRANS";
    );
command.Parameters.Add("@OrdID", SqlDbType.NVarChar, 15);
command.Parameters.Add("@CustID", SqlDbType.VarChar, 15);
command.Parameters["@CustID"].Value = cmbCust.SelectedText;

command.Parameters.Add("@OrdDt", SqlDbType.DateTime);
command.Parameters["@OrdDt"].Value = dtOrdDt.Text;

command.Parameters.Add("@ShipDt", SqlDbType.DateTime);
command.Parameters["@ShipDt"].Value =dtShipDt.Text;

command.Parameters.Add("@PrdId", SqlDbType.NVarChar, 5, "ProductID");
command.Parameters.Add("@Up", SqlDbType.VarChar, 50, "UnitPrice");
command.Parameters.Add("@Qty", SqlDbType.VarChar, 20, "Quantity");
sqlDataMaster.InsertCommand = command;