[我在学php之三]Po上自己写的数据库类，方便以后进行查找。

class mysql{    private $conn; //私有化 变量$conn    private $db_host; //主机    private $db_user;    private $db_password;    private $db_name; //数据库名称    function __construct($db_host,$db_user,$db_password,$db_name){        //构造函数，传入 类中的connect函数中        $this->db_host = $db_host;        $this->db_user = $db_user;        $this->db_password = $db_password;        $this->db_name = $db_name;        $this->connect();    }    function connect(){        //数据库连接函数        $this->conn = mysql_connect($this->db_host,$this->db_user,$this->db_password) or die("数据库连接失败".mysql_errno().":".mysql_error());        mysql_select_db($this->db_name,$this->conn) or die('打开数据库失败').mysql_error();        mysql_set_charset('utf8');        return $this->conn;    }    //插入数据库,$table(数据库名称),$array    function insert($table,$array){        $keys = "`".implode("`,`", array_keys($array))."`"; //调取数组中的键值        $vals = "'".implode("','", array_values($array))."'"; //调去数组中的数值        $sql = "insert into {$table} ({$keys}) values({$vals})";        $query = mysql_query($sql);        return mysql_insert_id();    }    //删除指定数据    function delete($table,$id,$where=null){        //语句: delete from table where id = ....        $where = $where ==null?null:'where '.$where;        $sql = "delete from {$table} where id = {$id} limit 1";        $query = mysql_query($sql);        return $query;    }    //选择数据库    public function select($table,$array,$where=null){        //语句: select * from table where `user`='$user'......        foreach ($array as $key => $value) {            $select[] = '`'.$key.'`='.$value;        }        $select = implode(' and ', $select);        $where = $where == null?null:$where;        $sql = "select * from {$table} where ".$select.' '.$where;        return $sql;    }    //修改数据库    function update($table,$array,$where = null){        //语句: update table set `name`='kopa' where id = ....        foreach ($array as $key => $value) {            $string[] = '`'.$key.'`='.$value;        }        $string =implode('`,',$string);        $where = $where==null?null:" where ".$where;        $sql = "update {$table} set ".$string.$where;        return $sql;        // $query = mysql_query($sql);        // return $query;        // print_r("update {$table} set ".$string.$where);    }    //读取数据库总行数 mysql_num_row    function totalRow($sql){        $query = mysql_query($sql);        $result = mysql_num_rows($query);        return $result;    }    //读取数据库的数组    function fetch_array($sql){        $query = mysql_query($sql);        $res = mysql_fetch_array($query);        return $res;    }}$db = new mysql("localhost",'root','3363064','ctxy');