Reinstate supplemental remarks (System.D*) (#12708)

Author: gewarren

add/media/gdip-art10.gif

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net10.0</TargetFramework>
+  </PropertyGroup>
+
+</Project>

add/media/gdip-art12.gif

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+// <Snippet1>
+using System;
+using System.Data;
+
+class Program
+{
+    static void Main()
+    {
+        // Create two tables and add them into the DataSet.
+        DataTable orderTable = CreateOrderTable();
+        DataTable orderDetailTable = CreateOrderDetailTable();
+        DataSet salesSet = new();
+        salesSet.Tables.Add(orderTable);
+        salesSet.Tables.Add(orderDetailTable);
+
+        // Set the relations between the tables
+        // and create the related constraint.
+        salesSet.Relations.Add(
+            "OrderOrderDetail",
+            orderTable.Columns["OrderId"],
+            orderDetailTable.Columns["OrderId"],
+            true);
+
+        Console.WriteLine("After creating the foreign key constraint, " +
+            "you'll see the following error if you insert " +
+            "an order detail with the wrong OrderId:\n");
+        try
+        {
+            DataRow errorRow = orderDetailTable.NewRow();
+            errorRow[0] = 1;
+            errorRow[1] = "O0007";
+            orderDetailTable.Rows.Add(errorRow);
+        }
+        catch (Exception e)
+        {
+            Console.WriteLine(e.Message);
+        }
+        Console.WriteLine();
+
+        // Insert the rows into the table.
+        InsertOrders(orderTable);
+        InsertOrderDetails(orderDetailTable);
+
+        Console.WriteLine("The initial Order table.");
+        ShowTable(orderTable);
+
+        Console.WriteLine("The OrderDetail table.");
+        ShowTable(orderDetailTable);
+
+        // Use the Aggregate-Sum on the child table column to get the result.
+        DataColumn colSub = new("SubTotal", typeof(decimal), "Sum(Child.LineTotal)");
+        orderTable.Columns.Add(colSub);
+
+        // Compute the tax by referencing the SubTotal expression column.
+        DataColumn colTax = new("Tax", typeof(decimal), "SubTotal*0.1");
+        orderTable.Columns.Add(colTax);
+
+        // If the OrderId is 'Total', compute the amount due on all orders; otherwise, compute the amount due on this order.
+        DataColumn colTotal = new(
+            "TotalDue",
+            typeof(decimal),
+            "IIF(OrderId='Total',Sum(SubTotal)+Sum(Tax),SubTotal+Tax)");
+        orderTable.Columns.Add(colTotal);
+
+        DataRow row = orderTable.NewRow();
+        row["OrderId"] = "Total";
+        orderTable.Rows.Add(row);
+
+        Console.WriteLine("The Order table with the expression columns.");
+        ShowTable(orderTable);
+
+        Console.WriteLine("Press any key to exit.....");
+        Console.ReadKey();
+    }
+
+    private static DataTable CreateOrderTable()
+    {
+        DataTable orderTable = new("Order");
+
+        // Define the columns one at a time.
+        DataColumn colId = new("OrderId", typeof(string));
+        orderTable.Columns.Add(colId);
+
+        DataColumn colDate = new("OrderDate", typeof(DateTime));
+        orderTable.Columns.Add(colDate);
+
+        // Set the OrderId column as the primary key.
+        orderTable.PrimaryKey = [colId];
+
+        return orderTable;
+    }
+
+    private static DataTable CreateOrderDetailTable()
+    {
+        DataTable orderDetailTable = new("OrderDetail");
+
+        // Define all the columns at once.
+        DataColumn[] cols =
+        [
+            new DataColumn("OrderDetailId", typeof(int)),
+            new DataColumn("OrderId", typeof(string)),
+            new DataColumn("Product", typeof(string)),
+            new DataColumn("UnitPrice", typeof(decimal)),
+            new DataColumn("OrderQty", typeof(int)),
+            new DataColumn("LineTotal", typeof(decimal), "UnitPrice*OrderQty")
+        ];
+
+        orderDetailTable.Columns.AddRange(cols);
+        orderDetailTable.PrimaryKey = [orderDetailTable.Columns["OrderDetailId"]];
+        return orderDetailTable;
+    }
+
+    private static void InsertOrders(DataTable orderTable)
+    {
+        // Add one row at a time.
+        DataRow row1 = orderTable.NewRow();
+        row1["OrderId"] = "O0001";
+        row1["OrderDate"] = new DateTime(2013, 3, 1);
+        orderTable.Rows.Add(row1);
+
+        DataRow row2 = orderTable.NewRow();
+        row2["OrderId"] = "O0002";
+        row2["OrderDate"] = new DateTime(2013, 3, 12);
+        orderTable.Rows.Add(row2);
+
+        DataRow row3 = orderTable.NewRow();
+        row3["OrderId"] = "O0003";
+        row3["OrderDate"] = new DateTime(2013, 3, 20);
+        orderTable.Rows.Add(row3);
+    }
+
+    private static void InsertOrderDetails(DataTable orderDetailTable)
+    {
+        // Use an Object array to insert all the rows.
+        // Values in the array are matched sequentially to the columns,
+        // based on the order in which they appear in the table.
+        object[][] rows =
+        [
+            [1, "O0001", "Mountain Bike", 1419.5, 36],
+            [2, "O0001", "Road Bike", 1233.6, 16],
+            [3, "O0001", "Touring Bike", 1653.3, 32],
+            [4, "O0002", "Mountain Bike", 1419.5, 24],
+            [5, "O0002", "Road Bike", 1233.6, 12],
+            [6, "O0003", "Mountain Bike", 1419.5, 48],
+            [7, "O0003", "Touring Bike", 1653.3, 8],
+        ];
+
+        foreach (object[] row in rows)
+        {
+            orderDetailTable.Rows.Add(row);
+        }
+    }
+
+    private static void ShowTable(DataTable table)
+    {
+        foreach (DataColumn col in table.Columns)
+        {
+            Console.Write("{0,-14}", col.ColumnName);
+        }
+        Console.WriteLine();
+
+        foreach (DataRow row in table.Rows)
+        {
+            foreach (DataColumn col in table.Columns)
+            {
+                if (col.DataType.Equals(typeof(DateTime)))
+                    Console.Write("{0,-14:d}", row[col]);
+                else if (col.DataType.Equals(typeof(decimal)))
+                    Console.Write("{0,-14:C}", row[col]);
+                else
+                    Console.Write("{0,-14}", row[col]);
+            }
+            Console.WriteLine();
+        }
+        Console.WriteLine();
+    }
+}
+// </Snippet1>

snippets/csharp/System.Data/DataTable/Overview/project.csproj

@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>net6.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <Nullable>enable</Nullable>
     <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <StartupObject>Demo.Program</StartupObject>