Asp.net DataList associates two-level menu Binding data

In this example, we will talk about using datalist to bind controls. Because I just learned this stuff, please give me some advice.
Asp tutorial. net code

Private void dataload ()

{

Dataset ds = new dataset ();

String SQL = "select * from partent ";

Sqlconnection con = new sqlconnection ("data source = pc-200912151837; initial catalog = test; integrated security = true ");

Sqldataadapter da = new sqldataadapter (SQL, con );

Da. fill (ds, "xinghao ");
String sql2 = "select * from parent ";

Sqldataadapter da2 = new sqldataadapter (sql2, con );

Da2.fill (ds, "parent ");

// This sentence is the most important. It seems that the relationship between two tables is established by id, and then the data is loaded.
Ds. relations. add ("myreation", ds. tables ["son"]. columns ["son_id"], ds. tables ["parent"]. columns ["parent_id"]);

Datalist. datasource = ds. tables ["son"]. defaultview;

Datalist. databind ();

}

 

Database tutorial code:

　　

Create table partent

(Partent_id int not null primary key, primary key id

Partent_name varchar (50) not null

)

Create table son

(

Son_id id not null primary key, primary key tid

Son_name varchar (50) not null,

Partent_id not null // id associated with partent

)