How to store session in Sql Server data base Using Asp.Net4.0

string admin="admin";
session["data"]=admin;

if(session["data"]!=null)
{

string  sql="insert into table values('"+session["data"].tostring().trim()+"')";

sqlconnection con=new sqlconnection(connectionstring);

con.open();

sqlcommand com=new sqlcommand(sql,con);

com.ExecuteNonQuery();

con.close();
}