我正在尝试创建一个用于在PHP上执行oracle sql语句的类。

这是我的index.php，我正在尝试调用我的函数

 <?php  
    include "dbaseconn/dbcontrol.php";
    $DbControl = new DbControl;
    $DbControl->execute(" SELECT * FROM SAMPLE_TABLE");
        foreach($DbControl->data as $items)
        {
         echo $items['SAMPLE_COLUMN_NAME'];
        }
?>

和我的dbcontrol.php用于我的功能

<?php
class DbControl{
    public $dbstr ='(DESCRIPTION = 
                (ADDRESS_LIST = 
                            (ADDRESS = (COMMUNITY = tcp.world)(PROTOCOL = TCP)(HOST = XX.XXX.XXX.XX)(PORT = XXXX))
                    )
                    (CONNECT_DATA = 
                      (SID = XXXXX)
                    )
                  )';

        public $user = "XXXXX";
        public $password = "XXXXX";

        function connect(){
            $this->connection = oci_connect($this->user,$this->password,$this->dbstr) or die(oci_error());
        }

    function execute($query){
        $this -> connect(); //Database Connect
        $this -> statement = oci_parse($this->connection,$query); //prepare the statement
        $this -> execute = oci_execute($this -> statement); //execute the statement
        $this -> totalRows = oci_num_rows($this -> statement); //get total number of rows
        $this -> data = array();
        if($this -> totalRows > 0){
                            //fetch data
                while($result = oci_fetch_array($this->statement)){
                    $this -> data[] = $result;
                }
        }
    }   
}

?>

我不确定似乎有什么问题。但是每次我运行这个。页面上未显示任何内容。没有结果，没有数据。但是我确信数据库中有数据。