what are the different methods of inserting data into sql server using asp.net ?

You can Google out for the "different ways" and they will return a bunch of results for you. I don't know many of them, but one is the default ASP.NET way of doing it. Otherwise you can use the .NET method.

ASP.NET way

In ASP.NET way you use the Database class[^] of the WebMatrix.Data namespace. The example code is,

// open the connection
var db = Database.Open("databaseName");
// create a query
var selectQuery = "SELECT * FROM table_name";
// select the results
var result = db.Query(selectQuery);

.NET way

In .NET you can use the System.Data.SqlClient[^] namespace to work with the Databases. It exposes many classes and methods to work with the SQL server. You can use them to manipulate the data in your SQL server. Connection Strings are used to connect to the database (or the server).

using (SqlConnection conn = new SqlConnection("connectionString")) {
   conn.Open();
   // connection opened, 
   // create SqlCommands and work.
}

This .NET method can be understood from my article. Please have a look at this article[^].