PHP設(shè)計(jì)模式-DAO (Data Access Objects) 數(shù)據(jù)訪問(wèn)對(duì)象模式

stonezhu 發(fā)布于2019-06-27 15:32 / 2419人閱讀

整理一下自己的學(xué)習(xí)Aaron Saray 寫的PHP設(shè)計(jì)模式一些demo和自己的理解。大佬看完如果發(fā)現(xiàn)鄙人理解有誤請(qǐng)立即指出，感謝拍磚，跪求鞭打

/**
 * DAO (Data Access Objects) 數(shù)據(jù)訪問(wèn)對(duì)象
 * -------------------------------------
 * ** 來(lái)自說(shuō)明 **
 *
 * 數(shù)據(jù)訪問(wèn)對(duì)象設(shè)計(jì)模式描述了如何創(chuàng)建提供透明訪問(wèn)任何數(shù)據(jù)源的對(duì)象
 *
 * 目的是解決下列兩種特定的問(wèn)題：
 *     1. 重復(fù)
 *  2. 數(shù)據(jù)源抽象化
 *  數(shù)據(jù)訪問(wèn)對(duì)象模式提供數(shù)據(jù)庫(kù)抽象層
 *  現(xiàn)在，應(yīng)用程序的主要處理代碼不再考慮數(shù)據(jù)庫(kù)引擎或表關(guān)系
 *  調(diào)用這種對(duì)象的公共方法會(huì)返回任何數(shù)據(jù)類型，不用考慮內(nèi)在SQL所需的類型
 * 
 * ===================================== 
 * ** 應(yīng)用場(chǎng)景 **
 *
 * 數(shù)據(jù)訪問(wèn)
 * 
 * -------------------------------------
 * 
 * @version ${Id}$
 * @author Shaowei Pu <54268491@qq.com>
 */

abstract class baseDao{
    /**
     * [$_connection 連接對(duì)象]
     * @var [type]
     */
    private $_connection;

    /**
     * [__construct 實(shí)例化數(shù)據(jù)庫(kù)連接]
     * @author         Shaowei Pu 
     * @CreateTime    2017-02-22T17:52:04+0800
     */
    public function __construct(){
        try{        
            $this->_connection = new PDO("mysql:dbname=mysql;host=localhost","root","pushaowei");
            $this->_connection->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        }catch(PDOException $e){
            die("error:".$e->getMessage());
        }   
    }
    /**
     * [feach description]
     * @author         Shaowei Pu 
     * @CreateTime    2017-02-22T18:01:48+0800
     * @return                              [type] [description]
     */
    public function fetch( $value , $key = ""){
        // SQL START
        $sql = "SELECT * FROM ".$this->_tablename." WHERE ".$key." = "".$value.""";
        // 輸出
        $dispose = $this->_connection->query($sql);
        return $dispose->fetch(PDO::FETCH_ASSOC);        
    }

}
class selectHandle extends baseDao{
    /**
     * [$_tablename 得到表名]
     * @var string
     */
    protected $_tablename = "db";

    /**
     * [getValue description]
     * @author         Shaowei Pu 
     * @CreateTime    2017-02-22T18:06:58+0800
     * @param                               [type] $value [description]
     * @return                              [type]        [description]
     */
    public function getDbValue( $value ){
        $result = parent::fetch( $value, "Host" );
        return $result;
    }
}

$select = new selectHandle;
var_dump($select->getDbValue("localhost"));

/* 
+----------------------------------------------------------------------
|    array (size=22)
|      "Host" => string "localhost" (length=9)
|      "Db" => string "sys" (length=3)
|      "User" => string "mysql.sys" (length=9)
|      "Select_priv" => string "N" (length=1)
|      "Insert_priv" => string "N" (length=1)
|      "Update_priv" => string "N" (length=1)
|      "Delete_priv" => string "N" (length=1)
|      "Create_priv" => string "N" (length=1)
|      "Drop_priv" => string "N" (length=1)
|      "Grant_priv" => string "N" (length=1)
|      "References_priv" => string "N" (length=1)
|      "Index_priv" => string "N" (length=1)
|      "Alter_priv" => string "N" (length=1)
|      "Create_tmp_table_priv" => string "N" (length=1)
|      "Lock_tables_priv" => string "N" (length=1)
|      "Create_view_priv" => string "N" (length=1)
|      "Show_view_priv" => string "N" (length=1)
|      "Create_routine_priv" => string "N" (length=1)
|      "Alter_routine_priv" => string "N" (length=1)
|      "Execute_priv" => string "N" (length=1)
|      "Event_priv" => string "N" (length=1)
|      "Trigger_priv" => string "Y" (length=1)
+----------------------------------------------------------------------
*/