ADO.NET 2.0 Dataset和Datatable 新功能新特性

1.新的索引引擎更快的执行效率
   下面这段代码在2003中需要157秒，在2005中只要11秒就可以完成：

DataSet ds = new DataSet();

            ds.Tables.Add("BigTable");
            ds.Tables[0].Columns.Add("ID", Type.GetType("System.Int32"));
            ds.Tables[0].Columns["ID"].Unique = true;
            ds.Tables[0].Columns.Add("Value", Type.GetType("System.Int32"));

            Cursor.Current = Cursors.WaitCursor;

            DateTime datBegin = DateTime.Now;

            Random rand = new Random();
            int i, intValue;
            DataRow dr;

            for (i = 1; i <= 500000; i++)
            {
                try
                {
                    intValue = rand.Next();

                    dr = ds.Tables[0].NewRow();

                    dr["ID"] = intValue;
                    dr["Value"] = intValue;

                    ds.Tables[0].Rows.Add(dr);
                }
                catch { }
            }

            Cursor.Current = Cursors.Default;

            MessageBox.Show("Elapsed Time: " + (DateTime.Now - datBegin).Seconds.ToString());
            MessageBox.Show("count = " + ds.Tables[0].Rows.Count.ToString());

2.Dataset可以序列化为二进制文件

 string connstr = "server=(local);database=northwind;integrated security=true;async=true";

            DataSet ds = new DataSet();
            SqlDataAdapter dadpt = new SqlDataAdapter("select * from [order details]", connstr);
            dadpt.Fill(ds);

            BinaryFormatter bf = new BinaryFormatter();
            FileStream fs = new FileStream(@"c:\xml1.txt",FileMode.OpenOrCreate);

            ds.RemotingFormat = SerializationFormat.Binary;

            bf.Serialize(fs,ds);     

3.更独立的Datatable
  DataTable Write XML

 string connstr = "server=(local);database=northwind;integrated security=true;async=true";
            SqlDataAdapter dadpt = new SqlDataAdapter("select * from [order details]", connstr);
            DataTable dt = new DataTable("Customer");
            dadpt.Fill(dt);

            dt.WriteXml(@"c:\DataTable.xml",true);
            dt.WriteXmlSchema(@"c:\DataTableSchema.xml");

   DataTable Read XML

 StreamReader sr = new StreamReader(@"C:\DataTableSchema.xml");

            DataTable dt = new DataTable();
            dt.ReadXmlSchema(sr);

            dt.ReadXml(new StreamReader(@"c:\dataTable.xml"));

            this.dataGridView1.DataSource = dt;

    DataTable Merge

 string connstr = "server=(local);database=northwind;integrated security=true;async=true";
            SqlDataAdapter dadpt = new SqlDataAdapter("select * from customers", connstr);
            DataTable dt = new DataTable("Customer");
            dadpt.Fill(dt);

            SqlDataAdapter dadpt1 = new SqlDataAdapter("select * from customers", connstr);
            DataTable dt1 = new DataTable("Customer1");
            dadpt1.Fill(dt1);

            dt.Merge(dt1);

            this.dataGridView1.DataSource = dt;

  DataTable Load DataReader

 string connstr = "server=(local);database=northwind;integrated security=true;async=true";
            SqlConnection conn = new SqlConnection(connstr);
            conn.Open();
            SqlCommand cmd = new SqlCommand("select * from [order details]", conn);
            SqlDataReader dr = cmd.ExecuteReader();

            DataTable dt = new DataTable("Customer");
            dt.Load(dr);

            this.dataGridView1.DataSource = dt;