Csharp/C Sharp/Database ADO.net/DataRelation

More than one Relations

<source lang="csharp">

using System; using System.Data; using System.Data.SqlClient; using System.Collections.Generic; using System.Text; class Program {

   static void Main(string[] args) {
       SqlConnection thisConnection = new SqlConnection(@"Server=(local)\sqlexpress;Integrated Security=True;" +
            "Database=northwind");
       DataSet thisDataSet = new DataSet();
       SqlDataAdapter custAdapter = new SqlDataAdapter("SELECT * FROM Customers", thisConnection);
       custAdapter.Fill(thisDataSet, "Customers");
       SqlDataAdapter orderAdapter = new SqlDataAdapter("SELECT * FROM Orders", thisConnection);
       orderAdapter.Fill(thisDataSet, "Orders");
       SqlDataAdapter detailAdapter = new SqlDataAdapter("SELECT * FROM [Order Details]", thisConnection);
       detailAdapter.Fill(thisDataSet, "Order Details");
       SqlDataAdapter prodAdapter = new SqlDataAdapter("SELECT * FROM Products", thisConnection);
       prodAdapter.Fill(thisDataSet, "Products");
       DataRelation custOrderRel = thisDataSet.Relations.Add("CustOrders",
                   thisDataSet.Tables["Customers"].Columns["CustomerID"],
                   thisDataSet.Tables["Orders"].Columns["CustomerID"]);
       DataRelation orderDetailRel = thisDataSet.Relations.Add("OrderDetail",
                   thisDataSet.Tables["Orders"].Columns["OrderID"],
                   thisDataSet.Tables["Order Details"].Columns["OrderID"]);
       DataRelation orderProductRel = thisDataSet.Relations.Add(
         "OrderProducts", thisDataSet.Tables["Products"].Columns["ProductID"],
          thisDataSet.Tables["Order Details"].Columns["ProductID"]);
       foreach (DataRow custRow in thisDataSet.Tables["Customers"].Rows) {
           Console.WriteLine("Customer ID: " + custRow["CustomerID"]);
           foreach (DataRow orderRow in custRow.GetChildRows(custOrderRel)) {
               Console.WriteLine("\tOrder ID: " + orderRow["OrderID"]);
               Console.WriteLine("\t\tOrder Date: " + orderRow["OrderDate"]);
               foreach (DataRow detailRow in
                        orderRow.GetChildRows(orderDetailRel)) {
                   Console.WriteLine("\t\tProduct: " +
                   detailRow.GetParentRow(orderProductRel)["ProductName"]);
                   Console.WriteLine("\t\tQuantity: " + detailRow["Quantity"]);
               }
           }
       }
       thisConnection.Close();
   }

}

      </source>

Setting the Nested property of a DataRelation to true

<source lang="csharp"> using System; using System.Data; using System.Data.SqlClient; class NestedXml {

 public static void Main()
 {
   SqlConnection mySqlConnection =new SqlConnection("server=(local)\\SQLEXPRESS;database=MyDatabase;Integrated Security=SSPI;");
   SqlCommand mySqlCommand = mySqlConnection.CreateCommand();
   mySqlCommand.rumandText =
     "SELECT TOP 2 EmployeeID, CompanyName " +
     "FROM Employee " +
     "ORDER BY EmployeeID;"  +
     "SELECT DeptID, EmployeeID, City " +
     "FROM Dept " +
     "WHERE EmployeeID IN (" +
     "  SELECT TOP 2 EmployeeID " +
     "  FROM Employee " +
     "  ORDER BY EmployeeID " +
     ")";
   SqlDataAdapter mySqlDataAdapter = new SqlDataAdapter();
   mySqlDataAdapter.SelectCommand = mySqlCommand;
   DataSet myDataSet = new DataSet();
   mySqlConnection.Open();
   int numberOfRows = mySqlDataAdapter.Fill(myDataSet);
   Console.WriteLine("numberOfRows = " + numberOfRows);
   mySqlConnection.Close();
   DataTable customersDT = myDataSet.Tables["Table"];
   DataTable ordersDT = myDataSet.Tables["Table1"];
   DataRelation customersDeptDataRel =
     new DataRelation(
       "EmployeeDept",
       customersDT.Columns["EmployeeID"],
       ordersDT.Columns["EmployeeID"]
     );
   myDataSet.Relations.Add(
     customersDeptDataRel
   );
   myDataSet.WriteXml("nonNestedXmlFile.xml");
   myDataSet.Relations["EmployeeDept"].Nested = true;
   myDataSet.WriteXml("nestedXmlFile.xml");
 }

}

      </source>

Set up DataRelation

<source lang="csharp">

using System; using System.Data; using System.Data.SqlClient; using System.Collections.Generic; using System.Text; class Program {

   static void Main(string[] args) {
       SqlConnection thisConnection = new SqlConnection(
            @"Server=(local)\sqlexpress;Integrated Security=True;" +
            "Database=northwind");
       SqlDataAdapter thisAdapter = new SqlDataAdapter(
            "SELECT CustomerID, CompanyName FROM Customers", thisConnection);
       SqlCommandBuilder thisBuilder = new SqlCommandBuilder(thisAdapter);
       DataSet thisDataSet = new DataSet();
       SqlDataAdapter custAdapter = new SqlDataAdapter(
            "SELECT * FROM Customers", thisConnection);
       SqlDataAdapter orderAdapter = new SqlDataAdapter(
            "SELECT * FROM Orders", thisConnection);
       custAdapter.Fill(thisDataSet, "Customers");
       orderAdapter.Fill(thisDataSet, "Orders");
       DataRelation custOrderRel = thisDataSet.Relations.Add("CustOrders",
            thisDataSet.Tables["Customers"].Columns["CustomerID"],
            thisDataSet.Tables["Orders"].Columns["CustomerID"]);
       foreach (DataRow custRow in thisDataSet.Tables["Customers"].Rows) {
           Console.WriteLine("Customer ID: " + custRow["CustomerID"] +
                             " Name: " + custRow["CompanyName"]);
           foreach (DataRow orderRow in custRow.GetChildRows(custOrderRel)) {
               Console.WriteLine("  Order ID: " + orderRow["OrderID"]);
           }
       }
       thisConnection.Close();
   }

}

      </source>