ADO.NET 2.0 Dataset和Datatable 新功能新特性

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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;