C# ado.net DataSet使用(五)

一、填充dataset

  class Program
     {
         private static string constr = "server=.;database=northwnd;integrated security=sspi";
         static void Main(string[] args)
         {
             string sql = "select contactname,companyname from customers";
             using (SqlConnection con=new SqlConnection(constr))
             {
                 SqlDataAdapter sda = new SqlDataAdapter(sql, constr);
                 DataSet ds = new DataSet();
                 sda.Fill(ds, "Customers");
                 foreach (DataRow row in ds.Tables["Customers"].Rows)
                     Console.WriteLine("'{0}' from {1}",
                         row[],
                         row[]);

                 con.Close();
             }
             Console.ReadLine();
         }
     }

二、dataset主外键关系

 class Program
     {
         private static string constr = "server=.;database=northwnd;integrated security=sspi";
         static void Main(string[] args)
         {
             string select = "SELECT * FROM Products";
             string sel2 = "SELECT * FROM Categories";
             using (SqlConnection con=new SqlConnection(constr))
             {
                 SqlDataAdapter da = new SqlDataAdapter(select, con);

                 DataSet ds = new DataSet();

                 ManufactureProductDataTable(ds);

                 da.Fill(ds, "Products");

                 foreach (DataRow row in ds.Tables["Products"].Rows)
                     Console.WriteLine("'{0}' from {1}",
                         row[],
                         row[]);

                 SqlDataAdapter da2 = new SqlDataAdapter(sel2, con);

                 ManufactureCategoryTable(ds);

                 da2.Fill(ds, "Categories");

                 AddForeignKeyConstraint(ds);

                 con.Close();
             }
         }
         public static void ManufactureProductDataTable(DataSet ds)
         {
             DataTable products = new DataTable("Products");
             products.Columns.Add(new DataColumn("ProductID", typeof(int)));
             products.Columns.Add(new DataColumn("ProductName", typeof(string)));
             products.Columns.Add(new DataColumn("SupplierID", typeof(int)));
             products.Columns.Add(new DataColumn("CategoryID", typeof(int)));
             products.Columns.Add(new DataColumn("QuantityPerUnit", typeof(string)));
             products.Columns.Add(new DataColumn("UnitPrice", typeof(decimal)));
             products.Columns.Add(new DataColumn("UnitsInStock", typeof(short)));
             products.Columns.Add(new DataColumn("UnitsOnOrder", typeof(short)));
             products.Columns.Add(new DataColumn("ReorderLevel", typeof(short)));
             products.Columns.Add(new DataColumn("Discontinued", typeof(bool)));

             ManufacturePrimaryKey(products);

             ds.Tables.Add(products);
         }
         public static void ManufacturePrimaryKey(DataTable dt)
         {
             DataColumn[] pk = new DataColumn[];
             pk[] = dt.Columns["ProductID"];
             dt.Constraints.Add(new UniqueConstraint("PK_Products", pk[]));
             dt.PrimaryKey = pk;
         }
         public static void ManufactureCategoryTable(DataSet ds)
         {
             DataTable categories = new DataTable("Categories");

             categories.Columns.Add(new DataColumn("CategoryID", typeof(int)));
             categories.Columns.Add(new DataColumn("CategoryName", typeof(string)));
             categories.Columns.Add(new DataColumn("Description", typeof(string)));

             categories.Constraints.Add(new UniqueConstraint("PK_Categories", categories.Columns["CategoryID"]));

             categories.PrimaryKey = new DataColumn[] { categories.Columns["CategoryID"] };

             ds.Tables.Add(categories);

         }
         public static void AddForeignKeyConstraint(DataSet ds)
         {
             DataColumn parent = ds.Tables["Categories"].Columns["CategoryID"];
             DataColumn child = ds.Tables["Products"].Columns["CategoryID"];

             ForeignKeyConstraint fk = new ForeignKeyConstraint("FK_Product_CategoryID", parent, child);

             fk.UpdateRule = Rule.Cascade;
             fk.DeleteRule = Rule.SetNull;

             // Create the constraint
             // If this fails, you have a row in the products table with no associated category
             ds.Tables["Products"].Constraints.Add(fk);

         }
     }

三、数据关联关系

    class Program
     {
         static void Main(string[] args)
         {

             DataSet ds = CreateDataSetWithRelationships();

             DataRow aBuilding = ds.Tables["Building"].NewRow();

             aBuilding["BuildingID"] = ;
             aBuilding["Name"] = "The Lowry";

             ds.Tables["Building"].Rows.Add(aBuilding);

             DataRow aRoom = ds.Tables["Room"].NewRow();

             aRoom["RoomID"] = ;
             aRoom["Name"] = "Reception";
             aRoom["BuildingID"] = ;

             ds.Tables["Room"].Rows.Add(aRoom);

             aRoom = ds.Tables["Room"].NewRow();
             aRoom["RoomID"] = ;
             aRoom["Name"] = "The Modern Art Gallery";
             aRoom["BuildingID"] = ;

             ds.Tables["Room"].Rows.Add(aRoom);

             foreach (DataRow theBuilding in ds.Tables["Building"].Rows)
             {
                 DataRow[] children = theBuilding.GetChildRows("Rooms");
                 int roomCount = children.Length;

                 Console.WriteLine("Building {0} contains {1} room{2}",
                     theBuilding["Name"],
                     roomCount,
                     roomCount >  ? "s" : "");

                 foreach (DataRow theRoom in children)
                     Console.WriteLine("Room: {0}", theRoom["Name"]);
             }

             foreach (DataRow theRoom in ds.Tables["Room"].Rows)
             {
                 DataRow[] parents = theRoom.GetParentRows("Rooms");

                 foreach (DataRow theBuilding in parents)
                     Console.WriteLine("Room {0} is contained in building {1}", theRoom["Name"], theBuilding["Name"]);
             }
         }
         public static DataSet CreateDataSetWithRelationships()
         {
             DataSet ds = new DataSet("Relationships");

             ds.Tables.Add(CreateBuildingTable());
             ds.Tables.Add(CreateRoomTable());

             ds.Relations.Add("Rooms", ds.Tables["Building"].Columns["BuildingID"], ds.Tables["Room"].Columns["BuildingID"]);

             return ds;
         }
         public static DataTable CreateBuildingTable()
         {
             DataTable aBuilding = new DataTable("Building");
             aBuilding.Columns.Add(new DataColumn("BuildingID", typeof(int)));
             aBuilding.Columns.Add(new DataColumn("Name", typeof(string)));
             aBuilding.Constraints.Add(new UniqueConstraint("PK_Building", aBuilding.Columns[]));
             aBuilding.PrimaryKey = new DataColumn[] { aBuilding.Columns[] };

             return aBuilding;
         }

         public static DataTable CreateRoomTable()
         {
             DataTable aRoom = new DataTable("Room");
             aRoom.Columns.Add(new DataColumn("RoomID", typeof(int)));
             aRoom.Columns.Add(new DataColumn("Name", typeof(string)));
             aRoom.Columns.Add(new DataColumn("BuildingID", typeof(int)));
             aRoom.Constraints.Add(new UniqueConstraint("PK_Room", aRoom.Columns[]));
             aRoom.PrimaryKey = new DataColumn[] { aRoom.Columns[] };

             return aRoom;
         }
     }