大家帮小弟我看一上这个php写mysql是那里出了有关问题

<center> <br /><form action="addData.php" method="post" target="_blank" ><br /><p>账号：<input name="u_user" title="text" size="32" maxlength="32" /></p><br /><p>密码：<input  name="u_pwd" title="text" size="32" maxlength="32"/></p>
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                <br /><input type="submit" value="注册" /><input type="reset" value="清空" /><br /></form></center>

    <?php   <br />    /////////////////和mysql建立链接  <br />    $host = "localhost";$user="root";$pwd="";$DataBaseName="db_appdata";$db_name="appdata";<br />    $con = mysql_connect($host,$user,$pwd);  <br />     if (!$con)    <br />        {    <br />        die('连接数据库失败： ' . mysql_error());   <br />        }   <br />    mysql_select_db($DataBaseName, $con);    //选取数据库  <br />    ////////////////////向表内插入数据  <br />    mysql_query("INSERT INTO $db_name (Name, pwd)  <br />     VALUES (.trim($_POST["u_user"]), .trim($_POST["u_pwd"])");  <br />     echo "添加成功"; <br />    //关闭连接  <br />    mysql_close($con);?>