[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‘);