PHP：致命错误：调用非对象上的成员函数[重复]

在这里遇到一个非常奇怪的错误，我正在编写一个平面文件数据库类，这一切都工作正常，直到我刷新，现在我不断收到此消息：

致命错误：调用非对象上的成员函数 name()/home/reithg/public_html/test/engine/class.database.php在线的50

我按如下方式调用该类：

<?php
ini_set('display_errors', '1');

require('engine/class.database.php');

$config = new Config("lessons", array('first', 'second', 'third', 'fourth'), "data/");
$db = new Database($config, true);

print("Querying DB for 'theta' no exclusions: <br />");
print_r($db->query('theta', NULL, NULL));

print("<p /> Querying DB for 'theta' in column 'second': <br />");
print_r($db->query('theta', 'second', NULL));

print("<p /> Querying DB for first two rows: <br />");
print_r($db->getRows(2));

print("<p /> Querying DB for last three rows: <br />");
print_r($db->getRows(3, true));

print("<p /> Cleaning data for safe DB input: <br />");
$testInput = array('escape|these||delimiters','and\these\\slashes','and\0these\0nulls',"don't, forget quotes");
print("input: ");
print_r($testInput);
echo("<br />output: ");
print($db->addRow($testInput));
?>

这是我的类.数据库.php

<?php
require('class.config.php');
require('class.column.php');

    class Database {
        private
            $_config,
            $_pointer;

        public function __construct(Config $config)  {
            $this->_config = $config;
            return true;
        }

        private function connect($method) {
            if (!($this->_pointer = @fopen($this->_config->db(), $method)))
            echo("Unable to connect to database");
        }

        private function disconnect() {
            fclose($this->_pointer);
        }

        private function lock($method) {
            if(flock($this->_pointer, $method))
                return true;
            return false;
        }

        private function unlock() {
            flock($this->_pointer, LOCK_UN);
        }

        private function cleanInput($input) {   
            $data = array_map(array($this, 'escapeData'), $input);
            $output = implode($this->_config->delimiter(), $data)."\r\n";
            return $output;
        }

        private function escapeData($data) 
        {
            $search = array('\\', '"', "'", '\\0', '\n', $this->_config->delimiter());
            $replace = array('\\\\', '\"', "\'", '\\0', '\\n', '\\'.$this->_config->delimiter());
            $output = str_replace(array_unique($search), array_unique($replace), $data);
            return $output;
        }

        private function formatRow($data) {
            foreach($data as $key => $value) {
                $row[$this->_config->columns($key, "position")->name()] = $value;
            }
            return $row;
        }

        public function dumpToArray() {
            $arrayDump;
            foreach(file($this->_config->db(), FILE_IGNORE_NEW_LINES | FILE_SKIP_EMPTY_LINES) as $row => $content)
                $arrayDump[$row] = formatRow(explode($this->_config->delimiter(),$content));
            return $arrayDump;
        }

        public function addRow(array $data) {
            $this->connect('ab');
            if($this->lock(LOCK_EX)) {
                // fwrite($this->_pointer, $this->cleanInput($data));
                echo($this->cleanInput($data));
                $this->unlock();
                $this->disconnect();
                return true;
            } else {
                $this->disconnect();
                return false;
            }
        }

        public function query($value, $column = NULL, $limit = NULL) {
            $this->connect('rb');
            $results = array();
            while ((is_null($limit) || (count($results) < $limit)) && !feof($this->_pointer)) {
                $data = explode($this->_config->delimiter(), fgets($this->_pointer, 1024));
                if(!is_null($column)) {
                    if ($data[$this->_config->columns($column, "string")->index()] == $value)
                        array_push($results, $this->formatRow($data));
                } else {
                    if (in_array($value, $data))
                        array_push($results, $this->formatRow($data));
                }
            }
            $this->disconnect();
            switch (count($results)) {
                case 0;
                    return false;
                case 1;
                    return $results[0];
                default;
                    return $results;
            }
        }

        public function getRows($limit = 1, $reverse = false) {
            $this->connect('rb');
            $offset = 0;
            $results = array();
            if ($reverse) {
                while(count($results) < $limit && fseek($this->_pointer, $offset, SEEK_END) >= 0) {
                    $char = fgetc($this->_pointer);
                    if($char == "\n" || $char == "\r"){
                        $offset --;
                        $data = explode($this->_config->delimiter(), fgets($this->_pointer, 1024));
                        array_push($results, $this->formatRow($data));
                    }
                    $offset--;
                }
                $results = array_reverse($results);
            } else {
                while ((($limit === NULL) || (count($results) < $limit)) && !feof($this->_pointer)) {
                    $data = explode($this->_config->delimiter(), fgets($this->_pointer, 1024));
                    array_push($results, $this->formatRow($data));
                }
            }
            $this->disconnect();
            return $results;
        }
    }
?>

类.config.php

<?php
    class Config {
        private
            $_db,
            $_file,
            $_columns = array(),
            $_directory,
            $_delimiter;

        public function __construct($file, array $columns, $directory = NULL, $delimiter = "|")  {
            $this->_db = $directory.$file.".db";
            $this->defineColumns($columns);
            $this->_directory = $directory;
            $this->_delimiter = $delimiter;
        } 

        public function db() {
            return $this->_db;
        }

        public function delimiter() {
            return $this->_delimiter;
        }       

        private function defineColumns($constants) {
            for ($i=0;$i<count($constants);$i++) {
                if(in_array($constants[$i], $this->_columns))
                    die("Column names must be unique");
                $column = new Column($constants[$i], $i);
                $this->_columns[$column->name()] = $column;
            }
        }

        public function columns($index, $search = "string") {
            switch ($search) {
                case "string";
                    return $this->_columns[$index];
                    break;
                case "position";
                    $keys = array_keys($this->_columns);
                    return $this->_columns[$keys[$index]];
                    break;
                default;
                    return false;
            }   
        }
    }
?>

类.column.php

<?php
    class Column { 
        const
            ALL = "0",
            STRING = "1",
            NUMBER = "2",
            INT = "3",
            AUTO_INCREMENT = "4",
            CURRENT_TIME = "5";

        private
            $_type = ALL,
            $_name,
            $_index,
            $_maxChars = "256";

        public function __construct($name, $index, $type = NULL, $maxChars = NULL)  {
            $this->_name = $name;
            $this->_index = $index;
            if(!is_null($type))
                setDataType($type);
            if(!is_null($maxChars))
                setMaxChars($maxChars);
            return $this;
        }

        public function setDataType($type) {
            switch ($type) {
                case ALL;
                case STRING;
                case NUMBER;
                case INT;
                case AUTO_INCREMENT;
                case CURRENT_TIME;
                    $this->_type = $type;
                    break;
                default;
                    return false;
            }
        }

        public function auditData($data) {
            switch ($this->_type) {
                case ALL;
                    $output = $data;
                    break;
                case STRING;
                    $output = (string) $data;
                    break;
                case NUMBER;
                    $output = (float) $data;
                    break;
                case INT;
                    $output = (int) $data;
                    break;
                case AUTO_INCREMENT;
                    $output = (int) $data;
                    break;
                case CURRENT_TIME;
                    $output = time();
                    break;
                default;
                    return false;
            }
            return $output;
        }

        public function setMaxChars($maxChars) {
            if(is_int($maxChars)) {
                $this->_maxChars = $maxChars;
            }
        }

        public function name() {
            return $this->_name;
        }

        public function index() {
            return $this->_index;
        }
    }
?>

我知道这是很多代码，但我无法弄清楚为什么会突然发生这种情况，实际上是在一次刷新中而不对代码进行任何更改。即使我回溯到也有效的早期版本，这种情况也会发生。

当我尝试这样做时：

print($this->_config->columns($key, "position"));

它返回：

可捕获的致命错误：Column 类的对象无法转换 串入/home/reithg/public_html/test/engine/class.database.php *50号线*

这表明我正在表演name()在类 Column 的成员上，该类有一个名为的公共方法name()

当我做：

print($this->_config->columns($key, "position")->name());

它返回（每次一个单词，因为它在 foreach 循环中）；

第一 第二 第三 第四 第一 第二 第三 第四

所以它显然在它之前的 1 行工作。

答案是由于隐藏的字符位于课程.db file.

显示的错误与此无关，我要感谢所有花时间捐出两便士的人。