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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;