C# ado.net DataSet使用(五)

 1  class Program
 2     {
 3         private static string constr = "server=.;database=northwnd;integrated security=sspi";
 4         static void Main(string[] args)
 5         {
 6             string sql = "select contactname,companyname from customers";
 7             using (SqlConnection con=new SqlConnection(constr))
 8             {
 9                 SqlDataAdapter sda = new SqlDataAdapter(sql, constr);
10                 DataSet ds = new DataSet();
11                 sda.Fill(ds, "Customers");
12                 foreach (DataRow row in ds.Tables["Customers"].Rows)
13                     Console.WriteLine("‘{0}‘ from {1}",
14                         row[0],
15                         row[1]);
16 
17                 con.Close();
18             }
19             Console.ReadLine();
20         } 
21     }

 1 class Program
 2     {
 3         private static string constr = "server=.;database=northwnd;integrated security=sspi";
 4         static void Main(string[] args)
 5         {
 6             string select = "SELECT * FROM Products";
 7             string sel2 = "SELECT * FROM Categories";
 8             using (SqlConnection con=new SqlConnection(constr))
 9             {
10                 SqlDataAdapter da = new SqlDataAdapter(select, con);
11 
12                 DataSet ds = new DataSet();
13 
14               
15                 ManufactureProductDataTable(ds);
16 
17                 da.Fill(ds, "Products");
18 
19                 foreach (DataRow row in ds.Tables["Products"].Rows)
20                     Console.WriteLine("‘{0}‘ from {1}",
21                         row[0],
22                         row[1]);
23 
24                 SqlDataAdapter da2 = new SqlDataAdapter(sel2, con);
25 
26              
27                 ManufactureCategoryTable(ds);
28 
29                 da2.Fill(ds, "Categories");
30                  
31                 AddForeignKeyConstraint(ds);
32 
33                 con.Close();
34             }
35         }
36         public static void ManufactureProductDataTable(DataSet ds)
37         {
38             DataTable products = new DataTable("Products");
39             products.Columns.Add(new DataColumn("ProductID", typeof(int)));
40             products.Columns.Add(new DataColumn("ProductName", typeof(string)));
41             products.Columns.Add(new DataColumn("SupplierID", typeof(int)));
42             products.Columns.Add(new DataColumn("CategoryID", typeof(int)));
43             products.Columns.Add(new DataColumn("QuantityPerUnit", typeof(string)));
44             products.Columns.Add(new DataColumn("UnitPrice", typeof(decimal)));
45             products.Columns.Add(new DataColumn("UnitsInStock", typeof(short)));
46             products.Columns.Add(new DataColumn("UnitsOnOrder", typeof(short)));
47             products.Columns.Add(new DataColumn("ReorderLevel", typeof(short)));
48             products.Columns.Add(new DataColumn("Discontinued", typeof(bool)));
49 
50             ManufacturePrimaryKey(products);
51 
52             ds.Tables.Add(products);
53         }
54         public static void ManufacturePrimaryKey(DataTable dt)
55         {
56             DataColumn[] pk = new DataColumn[1];
57             pk[0] = dt.Columns["ProductID"];
58             dt.Constraints.Add(new UniqueConstraint("PK_Products", pk[0]));
59             dt.PrimaryKey = pk;
60         }
61         public static void ManufactureCategoryTable(DataSet ds)
62         {
63             DataTable categories = new DataTable("Categories");
64 
65             categories.Columns.Add(new DataColumn("CategoryID", typeof(int)));
66             categories.Columns.Add(new DataColumn("CategoryName", typeof(string)));
67             categories.Columns.Add(new DataColumn("Description", typeof(string)));
68 
69             categories.Constraints.Add(new UniqueConstraint("PK_Categories", categories.Columns["CategoryID"]));
70 
71             categories.PrimaryKey = new DataColumn[1] { categories.Columns["CategoryID"] };
72 
73             ds.Tables.Add(categories);
74 
75         }
76         public static void AddForeignKeyConstraint(DataSet ds)
77         {
78             DataColumn parent = ds.Tables["Categories"].Columns["CategoryID"];
79             DataColumn child = ds.Tables["Products"].Columns["CategoryID"];
80 
81             ForeignKeyConstraint fk = new ForeignKeyConstraint("FK_Product_CategoryID", parent, child);
82 
83             fk.UpdateRule = Rule.Cascade;
84             fk.DeleteRule = Rule.SetNull;
85 
86             // Create the constraint
87             // If this fails, you have a row in the products table with no associated category
88             ds.Tables["Products"].Constraints.Add(fk);
89 
90         }
91     }

 1    class Program
 2     {
 3         static void Main(string[] args)
 4         {
 5           
 6             DataSet ds = CreateDataSetWithRelationships();
 7 
 8            
 9             DataRow aBuilding = ds.Tables["Building"].NewRow();
10 
11             aBuilding["BuildingID"] = 1;
12             aBuilding["Name"] = "The Lowry";
13 
14             ds.Tables["Building"].Rows.Add(aBuilding);
15 
16         
17             DataRow aRoom = ds.Tables["Room"].NewRow();
18 
19             aRoom["RoomID"] = 1;
20             aRoom["Name"] = "Reception";
21             aRoom["BuildingID"] = 1;
22 
23             ds.Tables["Room"].Rows.Add(aRoom);
24 
25      
26             aRoom = ds.Tables["Room"].NewRow();
27             aRoom["RoomID"] = 2;
28             aRoom["Name"] = "The Modern Art Gallery";
29             aRoom["BuildingID"] = 1;
30 
31             ds.Tables["Room"].Rows.Add(aRoom);
32 
33          
34             foreach (DataRow theBuilding in ds.Tables["Building"].Rows)
35             {
36                 DataRow[] children = theBuilding.GetChildRows("Rooms");
37                 int roomCount = children.Length;
38 
39                 Console.WriteLine("Building {0} contains {1} room{2}",
40                     theBuilding["Name"],
41                     roomCount,
42                     roomCount > 1 ? "s" : "");
43 
44          
45                 foreach (DataRow theRoom in children)
46                     Console.WriteLine("Room: {0}", theRoom["Name"]);
47             }
48 
49          
50             foreach (DataRow theRoom in ds.Tables["Room"].Rows)
51             {
52                 DataRow[] parents = theRoom.GetParentRows("Rooms");
53 
54                 foreach (DataRow theBuilding in parents)
55                     Console.WriteLine("Room {0} is contained in building {1}", theRoom["Name"], theBuilding["Name"]);
56             }
57         }
58         public static DataSet CreateDataSetWithRelationships()
59         {
60             DataSet ds = new DataSet("Relationships");
61 
62             ds.Tables.Add(CreateBuildingTable());
63             ds.Tables.Add(CreateRoomTable());
64 
65            
66             ds.Relations.Add("Rooms", ds.Tables["Building"].Columns["BuildingID"], ds.Tables["Room"].Columns["BuildingID"]);
67 
68             return ds;
69         }
70         public static DataTable CreateBuildingTable()
71         {
72             DataTable aBuilding = new DataTable("Building");
73             aBuilding.Columns.Add(new DataColumn("BuildingID", typeof(int)));
74             aBuilding.Columns.Add(new DataColumn("Name", typeof(string)));
75             aBuilding.Constraints.Add(new UniqueConstraint("PK_Building", aBuilding.Columns[0]));
76             aBuilding.PrimaryKey = new DataColumn[] { aBuilding.Columns[0] };
77 
78             return aBuilding;
79         }
80 
81         public static DataTable CreateRoomTable()
82         {
83             DataTable aRoom = new DataTable("Room");
84             aRoom.Columns.Add(new DataColumn("RoomID", typeof(int)));
85             aRoom.Columns.Add(new DataColumn("Name", typeof(string)));
86             aRoom.Columns.Add(new DataColumn("BuildingID", typeof(int)));
87             aRoom.Constraints.Add(new UniqueConstraint("PK_Room", aRoom.Columns[0]));
88             aRoom.PrimaryKey = new DataColumn[] { aRoom.Columns[0] };
89 
90             return aRoom;
91         }
92     }