php如何进入数据库

<?php
$con=mysql_connect("localhost:3306","用户名（默认root）","密码");
if(mysql_error())
{
echo"数据库连接失败";
die();//终止运行
}
mysql_select_db("数据库名",$con);
if(mysql_errno())
{
echo"数据库连接失败";
die();
}
echo"数据库连接成功";
?>

<?php
$con=mysql_connect("localhost:3306","root","root")
or die("数据库连接失败<br>");
mysql_select_db("mysql_test",$con) or die("数据库连接失败！<br>");
mysql_query("set names &#39;gbk&#39;");//设置中文字符
$sql = "insert into customers(cust_id,cust_name,cust_sex,cust_address,cust_contact)";
$sql=$sql."values(null,&#39;李中华&#39;,&#39;0&#39;,&#39;深圳市&#39;,&#39;南山区&#39;)";
if(mysql_query($sql,$con)){
echo"数据库连接成功<br>";
}
else{
echo"数据库连接失败<br>";
}
?>