I'm just using a comment box for letting user to enter the comments, but now the user is tending to post as many comment, I just want the user to post only one time, So wat i think is before we inserting a comment in database we will check something to stop inserting one more time (Dont let place twice the same comment)

```
$query = "INSERT INTO comments(user_id,post_id,comments)"
            ."VALUES('".$user_id."','" .$post_id. "','" .$comment_text. "')";
$result = mysql_query($query) or die('Error'.mysql_error());

```