title: insert problem in C#, using sqlcommand
body: <p>when I run this sql:</p>
  
  <pre><code>insert into table1(ID,Name) values ('10','Saeed');
  </code></pre>
  
  <p>it seems that the record has been inserted, and if I read the table using (<code>select * from table1</code>) it shows me the inserted record, but after closing the program, it disappears.</p>
  
  <p>it's the code:</p>
  
  <pre><code>string constr="Data Source=.\\SQLEXPRESS;AttachDbFilename=|DataDirectory|" +   
      "\\Database1.mdf;Integrated Security=True;User Instance=True";
  
  SqlConnection con = new SqlConnection(constr);
  con.Open();
  
  SqlCommand cmd = new SqlCommand(
      "insert into st (ID,Name) values ('10','saeed');", con);
  
  cmd.ExecuteNonQuery();
  cmd.Close();
  </code></pre>
  
  <p>I inserted some records in it manually, and when I read the database, the manually inserted records exist.</p>
  
  <p>It is not a transaction problem wont be solved with a transaction!</p>