怎么在php中使用实体类

<?php
class BaseModel{
	private $_tableName;
	
	public function construct($tableName=""){
		$this->_tableName=$tableName;
	}
	
	public function getTableName(){
		return $this->_tableName;
	}
	
	public function getFieldsArray(){
		try {			
			$obj=json_decode(json_encode($this),true);  //此处可能会影响效率，但是为了去除类中的private属性，目前是这么做的
			$fieldsArray=array();
			foreach ($obj as $k=>$v){
				$fieldsArray[]=$k;
			}
			return $fieldsArray;
		} catch (Exception $e) {
			throw new Exception($e,3, $previous);
		}
	}
	
	
	public function find($condition=null){
		try {
			$sql="select ".implode(",",$this->getFieldsArray())." from ".$this->_tableName." ";
			if($condition){
				$sql.=" where ".$condition;
			}else {
				$obj=json_decode(json_encode($this),true);
				$fieldsArray=array();
				foreach ($obj as $k=>$v){
					if($v!=null && $v!=""){
						$fieldsArray[]=$k."='".$v."'";
					}
				}
				if(count($fieldsArray)>0){
					$sql.=" where ".implode(" and ", $fieldsArray);
				}
			}
			return $sql;	
		} catch (Exception $e) {
			throw new Exception($e,3, $previous);
		}
	}
}
?>

<?php
class MemberModel extends BaseModel{
	public $m_ID;
	public $m_Account;
	public $m_Pwd;
	public $m_TEL;
	public $m_UserID;
	public $m_ChannelID;
	public $m_Status;
	public $m_CreateTime;
	public $m_UpdateTime;
	
}
?>

	public function actionSelectMember(){
		try {
			$member=new MemberModel("T_Member");
			$member->m_Account=GetValue::getParam("Account");
			$member->m_Pwd=GetValue::getParam("Pwd");
			$result=MemberService::selectMember($member);
			if($result){
				Yii::app()->session["MemberID"]=$result["m_ID"];
				echo IMReturnStr::success();
			}else {
				echo IMReturnStr::GetInfo(false,"用户名或者密码错误");
			}
		} catch (Exception $e) {
			echo IMReturnStr::failure();
		}
	}

<p style="margin-bottom: 7px;">	public static function selectMember(MemberModel $member){<br/>		try {<br/>			return MemberDao::selectMember($member);<br/>		} catch (Exception $e) {<br/>			throw new Exception($e,4);<br/>		}<br/>	}</p>

	public static function selectMember(MemberModel $member){    //这里就是为什么要写类型了，写了类型可以拿到定义的类中的方法，否则虽然也可以直接写，但是没有自动提示，如果用的方法比较多，就很蛋疼了。
		try {
			$sql=$member->find();
			return YIISqlOper::queryRow($sql);
		} catch (Exception $e) {
			throw new Exception($e,4);
		}
	}