庫MySQLi包裝：fetch_field（）非對象

Question

我用下面的包裝上：

<?php 
/** 
* MysqliDb Class 
* 
* @category Database Access 
* @package MysqliDb 
* @author Jeffery Way <jeffrey@jeffrey-way.com> 
* @author Josh Campbell <jcampbell@ajillion.com> 
* @copyright Copyright (c) 2010 
* @license http://opensource.org/licenses/gpl-3.0.html GNU Public License 
* @version 1.1 
**/ 
class MysqliDb 
{ 
    /** 
    * Static instance of self 
    * 
    * @var MysqliDb 
    */ 
    protected static $_instance; 
    /** 
    * MySQLi instance 
    * 
    * @var mysqli 
    */ 
    protected $_mysqli; 
    /** 
    * The SQL query to be prepared and executed 
    * 
    * @var string 
    */ 
    protected $_query; 
    /** 
    * An array that holds where conditions 'fieldname' => 'value' 
    * 
    * @var array 
    */ 
    protected $_where = array(); 
    /** 
    * Dynamic type list for where condition values 
    * 
    * @var array 
    */ 
    protected $_whereTypeList; 
    /** 
    * Dynamic type list for table data values 
    * 
    * @var array 
    */ 
    protected $_paramTypeList; 
    /** 
    * Dynamic array that holds a combination of where condition/table data value types and parameter referances 
    * 
    * @var array 
    */ 
    protected $_bindParams = array(''); // Create the empty 0 index 

    /** 
    * @param string $host 
    * @param string $username 
    * @param string $password 
    * @param string $db 
    * @param int $port 
    */ 
    public function __construct($host, $username, $password, $db, $port = NULL) 
    { 
     if($port == NULL) 
      $port = ini_get('mysqli.default_port'); 

     $this->_mysqli = new mysqli($host, $username, $password, $db, $port) 
      or die('There was a problem connecting to the database'); 

     $this->_mysqli->set_charset('utf8'); 

     self::$_instance = $this; 
    } 

    /** 
    * A method of returning the static instance to allow access to the 
    * instantiated object from within another class. 
    * Inheriting this class would require reloading connection info. 
    * 
    * @uses $db = MySqliDb::getInstance(); 
    * 
    * @return object Returns the current instance. 
    */ 
    public static function getInstance() 
    { 
     return self::$_instance; 
    } 

    /** 
    * Reset states after an execution 
    * 
    * @return object Returns the current instance. 
    */ 
    protected function reset() 
    { 
     $this->_where = array(); 
     $this->_bindParams = array(''); // Create the empty 0 index 
     unset($this->_query); 
     unset($this->_whereTypeList); 
     unset($this->_paramTypeList); 
    } 

    /** 
    * Pass in a raw query and an array containing the parameters to bind to the prepaird statement. 
    * 
    * @param string $query  Contains a user-provided query. 
    * @param array $bindParams All variables to bind to the SQL statment. 
    * 
    * @return array Contains the returned rows from the query. 
    */ 
    public function rawQuery($query, $bindParams = null) 
    { 
     $this->_query = filter_var($query, FILTER_SANITIZE_STRING); 
     $stmt = $this->_prepareQuery(); 

     if (is_array($bindParams) === true) { 
      $params = array(''); // Create the empty 0 index 
      foreach ($bindParams as $prop => $val) { 
       $params[0] .= $this->_determineType($val); 
       array_push($params, $bindParams[$prop]); 
      } 

      call_user_func_array(array($stmt, 'bind_param'), $this->refValues($params)); 

     } 

     $stmt->execute(); 
     $this->reset(); 

     return $this->_dynamicBindResults($stmt); 
    } 

    /** 
    * 
    * @param string $query Contains a user-provided select query. 
    * @param int $numRows The number of rows total to return. 
    * 
    * @return array Contains the returned rows from the query. 
    */ 
    public function query($query, $numRows = null) 
    { 
     $this->_query = filter_var($query, FILTER_SANITIZE_STRING); 
     $stmt = $this->_buildQuery($numRows); 
     $stmt->execute(); 
     $this->reset(); 

     return $this->_dynamicBindResults($stmt); 
    } 

    /** 
    * A convenient SELECT * function. 
    * 
    * @param string $tableName The name of the database table to work with. 
    * @param integer $numRows The number of rows total to return. 
    * 
    * @return array Contains the returned rows from the select query. 
    */ 
    public function get($tableName, $numRows = null) 
    { 
     $this->_query = "SELECT * FROM $tableName"; 
     $stmt = $this->_buildQuery($numRows); 
     $stmt->execute(); 
     $this->reset(); 

     return $this->_dynamicBindResults($stmt); 
    } 

    /** 
    * 
    * @param <string $tableName The name of the table. 
    * @param array $insertData Data containing information for inserting into the DB. 
    * 
    * @return boolean Boolean indicating whether the insert query was completed succesfully. 
    */ 
    public function insert($tableName, $insertData) 
    { 
     $this->_query = "INSERT into $tableName"; 
     $stmt = $this->_buildQuery(null, $insertData); 
     $stmt->execute(); 
     $this->reset(); 

     return ($stmt->affected_rows > 0 ? $stmt->insert_id : false); 
    } 

    /** 
    * Update query. Be sure to first call the "where" method. 
    * 
    * @param string $tableName The name of the database table to work with. 
    * @param array $tableData Array of data to update the desired row. 
    * 
    * @return boolean 
    */ 
    public function update($tableName, $tableData) 
    { 
     $this->_query = "UPDATE $tableName SET "; 

     $stmt = $this->_buildQuery(null, $tableData); 
     $stmt->execute(); 
     $this->reset(); 

     return ($stmt->affected_rows > 0); 
    } 

    /** 
    * Delete query. Call the "where" method first. 
    * 
    * @param string $tableName The name of the database table to work with. 
    * @param integer $numRows The number of rows to delete. 
    * 
    * @return boolean Indicates success. 0 or 1. 
    */ 
    public function delete($tableName, $numRows = null) 
    { 
     $this->_query = "DELETE FROM $tableName"; 

     $stmt = $this->_buildQuery($numRows); 
     $stmt->execute(); 
     $this->reset(); 

     return ($stmt->affected_rows > 0); 
    } 

    /** 
    * This method allows you to specify multipl (method chaining optional) WHERE statements for SQL queries. 
    * 
    * @uses $MySqliDb->where('id', 7)->where('title', 'MyTitle'); 
    * 
    * @param string $whereProp The name of the database field. 
    * @param mixed $whereValue The value of the database field. 
    * 
    * @return MysqliDb 
    */ 
    public function where($whereProp, $whereValue) 
    { 
     $this->_where[$whereProp] = $whereValue; 
     return $this; 
    } 


    /** 
    * This methods returns the ID of the last inserted item 
    * 
    * @return integer The last inserted item ID. 
    */ 
    public function getInsertId() 
    { 
     return $this->_mysqli->insert_id; 
    } 

    /** 
    * Escape harmful characters which might affect a query. 
    * 
    * @param string $str The string to escape. 
    * 
    * @return string The escaped string. 
    */ 
    public function escape($str) 
    { 
     return $this->_mysqli->real_escape_string($str); 
    } 

    /** 
    * This method is needed for prepared statements. They require 
    * the data type of the field to be bound with "i" s", etc. 
    * This function takes the input, determines what type it is, 
    * and then updates the param_type. 
    * 
    * @param mixed $item Input to determine the type. 
    * 
    * @return string The joined parameter types. 
    */ 
    protected function _determineType($item) 
    { 
     switch (gettype($item)) { 
      case 'NULL': 
      case 'string': 
       return 's'; 
       break; 

      case 'integer': 
       return 'i'; 
       break; 

      case 'blob': 
       return 'b'; 
       break; 

      case 'double': 
       return 'd'; 
       break; 
     } 
     return ''; 
    } 

    /** 
    * Abstraction method that will compile the WHERE statement, 
    * any passed update data, and the desired rows. 
    * It then builds the SQL query. 
    * 
    * @param int $numRows The number of rows total to return. 
    * @param array $tableData Should contain an array of data for updating the database. 
    * 
    * @return mysqli_stmt Returns the $stmt object. 
    */ 
    protected function _buildQuery($numRows = null, $tableData = null) 
    { 
     $hasTableData = is_array($tableData); 
     $hasConditional = !empty($this->_where); 

     // Did the user call the "where" method? 
     if (!empty($this->_where)) { 

      // if update data was passed, filter through and create the SQL query, accordingly. 
      if ($hasTableData) { 
       $pos = strpos($this->_query, 'UPDATE'); 
       if ($pos !== false) { 
        foreach ($tableData as $prop => $value) { 
         // determines what data type the item is, for binding purposes. 
         $this->_paramTypeList .= $this->_determineType($value); 

         // prepares the reset of the SQL query. 
         $this->_query .= ($prop . ' = ?, '); 
        } 
        $this->_query = rtrim($this->_query, ', '); 
       } 
      } 

      //Prepair the where portion of the query 
      $this->_query .= ' WHERE '; 
      foreach ($this->_where as $column => $value) { 
       // Determines what data type the where column is, for binding purposes. 
       $this->_whereTypeList .= $this->_determineType($value); 

       // Prepares the reset of the SQL query. 
       $this->_query .= ($column . ' = ? AND '); 
      } 
      $this->_query = rtrim($this->_query, ' AND '); 
     } 

     // Determine if is INSERT query 
     if ($hasTableData) { 
      $pos = strpos($this->_query, 'INSERT'); 

      if ($pos !== false) { 
       //is insert statement 
       $keys = array_keys($tableData); 
       $values = array_values($tableData); 
       $num = count($keys); 

       // wrap values in quotes 
       foreach ($values as $key => $val) { 
        $values[$key] = "'{$val}'"; 
        $this->_paramTypeList .= $this->_determineType($val); 
       } 

       $this->_query .= '(' . implode($keys, ', ') . ')'; 
       $this->_query .= ' VALUES('; 
       while ($num !== 0) { 
        $this->_query .= '?, '; 
        $num--; 
       } 
       $this->_query = rtrim($this->_query, ', '); 
       $this->_query .= ')'; 
      } 
     } 

     // Did the user set a limit 
     if (isset($numRows)) { 
      $this->_query .= ' LIMIT ' . (int)$numRows; 
     } 

     // Prepare query 
     $stmt = $this->_prepareQuery(); 

     // Prepare table data bind parameters 
     if ($hasTableData) { 
      $this->_bindParams[0] = $this->_paramTypeList; 
      foreach ($tableData as $prop => $val) { 
       array_push($this->_bindParams, $tableData[$prop]); 
      } 
     } 
     // Prepare where condition bind parameters 
     if ($hasConditional) { 
      if ($this->_where) { 
       $this->_bindParams[0] .= $this->_whereTypeList; 
       foreach ($this->_where as $prop => $val) { 
        array_push($this->_bindParams, $this->_where[$prop]); 
       } 
      } 
     } 
     // Bind parameters to statment 
     if ($hasTableData || $hasConditional) { 
      call_user_func_array(array($stmt, 'bind_param'), $this->refValues($this->_bindParams)); 
     } 

     return $stmt; 
    } 

    /** 
    * This helper method takes care of prepared statements' "bind_result method 
    * , when the number of variables to pass is unknown. 
    * 
    * @param mysqli_stmt $stmt Equal to the prepared statement object. 
    * 
    * @return array The results of the SQL fetch. 
    */ 
    protected function _dynamicBindResults(mysqli_stmt $stmt) 
    { 
     $parameters = array(); 
     $results = array(); 

     $meta = $stmt->result_metadata(); 

     $row = array(); 
     while ($field = $meta->fetch_field()) { 
      $row[$field->name] = null; 
      $parameters[] = & $row[$field->name]; 
     } 

     call_user_func_array(array($stmt, 'bind_result'), $parameters); 

     while ($stmt->fetch()) { 
      $x = array(); 
      foreach ($row as $key => $val) { 
       $x[$key] = $val; 
      } 
      array_push($results, $x); 
     } 
     return $results; 
    } 

    /** 
    * Method attempts to prepare the SQL query 
    * and throws an error if there was a problem. 
    * 
    * @return mysqli_stmt 
    */ 
    protected function _prepareQuery() 
    { 
     if (!$stmt = $this->_mysqli->prepare($this->_query)) { 
      trigger_error("Problem preparing query ($this->_query) " . $this->_mysqli->error, E_USER_ERROR); 
     } 
     return $stmt; 
    } 

    /** 
    * Close connection 
    */ 
    public function __destruct() 
    { 
     $this->_mysqli->close(); 
    } 

    /** 
    * @param array $arr 
    * 
    * @return array 
    */ 
    protected function refValues($arr) 
    { 
     //Reference is required for PHP 5.3+ 
     if (strnatcmp(phpversion(), '5.3') >= 0) { 
      $refs = array(); 
      foreach ($arr as $key => $value) { 
       $refs[$key] = & $arr[$key]; 
      } 
      return $refs; 
     } 
     return $arr; 
    } 

} // END class 

從這個網址：https://github.com/ajillion/PHP-MySQLi-Database-Class。

我正在使用rawQuery方法。它在SELECT中工作正常，但是當我嘗試執行UPDATE時，出現以下錯誤：致命錯誤：在第419行的非對象中調用成員函數fetch_field（）（這是第7行後函數_dynamicBindResults）。這怎麼可能？

Answer 1

UPDATE，INSERT，DELETE不像SELECT查詢那樣返回結果。使用實施更新方法更新查詢：

$updateData = array(
    'fieldOne' => 'fieldValue', 
    'fieldTwo' => 'fieldValue' 
); 
$db->where('id', int); 
$results = $db->update('tableName', $updateData);