1 | <?php |
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2 | /** |
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3 | * DB.inc.php |
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4 | * code by strangecode :: www.strangecode.com :: this document contains copyrighted information |
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5 | * |
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6 | * DB abstraction layer. |
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7 | * |
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8 | * @author Quinn Comendant <quinn@strangecode.com> |
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9 | * @version 1.0.1 |
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10 | */ |
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11 | |
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12 | class DB { |
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13 | |
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14 | // If DB::connect has successfully opened a db connection. |
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15 | var $_connected = false; |
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16 | |
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17 | // Database handler. |
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18 | var $dbh; |
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19 | |
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20 | // Hash of DB parameters. |
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21 | var $_params = array(); |
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22 | |
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23 | // Default parameters. |
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24 | var $_param_defaults = array( |
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25 | |
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26 | // DB passwords should be set as apache environment variables in httpd.conf, readable only by root. |
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27 | 'db_server' => 'localhost', |
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28 | 'db_name' => null, |
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29 | 'db_user' => null, |
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30 | 'db_pass' => null, |
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31 | |
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32 | // Debugging. |
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33 | 'db_always_debug' => false, // TRUE = display all SQL queries. |
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34 | 'db_debug' => false, // TRUE = display db errors. |
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35 | 'db_die_on_failure' => false, // TRUE = script stops on db error. |
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36 | ); |
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37 | |
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38 | // Translate between HTML and MySQL character set names. |
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39 | var $mysql_character_sets = array( |
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40 | 'utf-8' => 'utf8', |
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41 | 'iso-8859-1' => 'latin1', |
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42 | ); |
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43 | |
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44 | // Caches. |
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45 | var $existing_tables; |
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46 | var $table_columns; |
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47 | |
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48 | /** |
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49 | * This method enforces the singleton pattern for this class. |
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50 | * |
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51 | * @return object Reference to the global SessionCache object. |
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52 | * @access public |
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53 | * @static |
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54 | */ |
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55 | function &getInstance() |
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56 | { |
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57 | static $instance = null; |
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58 | |
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59 | if ($instance === null) { |
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60 | $instance = new DB(); |
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61 | } |
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62 | |
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63 | return $instance; |
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64 | } |
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65 | |
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66 | /** |
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67 | * Constructor. |
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68 | */ |
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69 | function DB() |
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70 | { |
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71 | // Initialize default params. |
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72 | if (isset($params) && is_array($params)) { |
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73 | // Merge new parameters with old overriding only those passed. |
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74 | $this->_params = array_merge($this->_params, $params); |
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75 | } |
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76 | } |
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77 | |
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78 | /** |
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79 | * Set (or overwrite existing) parameters by passing an array of new parameters. |
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80 | * |
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81 | * @access public |
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82 | * |
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83 | * @param array $params Array of parameters (key => val pairs). |
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84 | */ |
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85 | function setParam($params) |
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86 | { |
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87 | if (!isset($this) || !is_a($this, 'DB') && !is_subclass_of($this, 'DB')) { |
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88 | $this =& DB::getInstance(); |
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89 | } |
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90 | |
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91 | if (isset($params) && is_array($params)) { |
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92 | // Merge new parameters with old overriding only those passed. |
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93 | $this->_params = array_merge($this->_params, $params); |
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94 | } else { |
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95 | App::logMsg(sprintf('Parameters are not an array: %s', $params), LOG_ERR, __FILE__, __LINE__); |
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96 | } |
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97 | } |
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98 | |
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99 | /** |
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100 | * Return the value of a parameter. |
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101 | * |
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102 | * @access public |
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103 | * |
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104 | * @param string $param The key of the parameter to return. |
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105 | * |
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106 | * @return mixed Parameter value. |
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107 | */ |
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108 | function getParam($param) |
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109 | { |
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110 | if (!isset($this) || !is_a($this, 'DB') && !is_subclass_of($this, 'DB')) { |
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111 | $this =& DB::getInstance(); |
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112 | } |
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113 | |
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114 | if (isset($this->_params[$param])) { |
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115 | return $this->_params[$param]; |
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116 | } else { |
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117 | App::logMsg(sprintf('Parameter is not set: %s', $param), LOG_DEBUG, __FILE__, __LINE__); |
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118 | return null; |
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119 | } |
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120 | } |
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121 | |
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122 | /** |
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123 | * Connect to database with credentials in params. |
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124 | * |
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125 | * @access public |
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126 | * @author Quinn Comendant <quinn@strangecode.com> |
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127 | * @since 28 Aug 2005 14:02:49 |
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128 | */ |
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129 | function connect() |
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130 | { |
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131 | if (!isset($this) || !is_a($this, 'DB') && !is_subclass_of($this, 'DB')) { |
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132 | $this =& DB::getInstance(); |
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133 | } |
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134 | |
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135 | if (!$this->getParam('db_name') || !$this->getParam('db_user') || !$this->getParam('db_pass')) { |
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136 | App::logMsg('Database credentials missing.', LOG_EMERG, __FILE__, __LINE__); |
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137 | return false; |
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138 | } |
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139 | |
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140 | // Connect to database. Always create a new link to the server. |
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141 | if ($this->dbh = mysql_connect($this->getParam('db_server'), $this->getParam('db_user'), $this->getParam('db_pass'), true)) { |
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142 | // Select database |
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143 | mysql_select_db($this->getParam('db_name'), $this->dbh); |
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144 | } |
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145 | |
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146 | // Test for connection errors. |
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147 | if (!$this->dbh || mysql_error($this->dbh)) { |
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148 | $mysql_error_msg = $this->dbh ? 'Codebase MySQL error: (' . mysql_errno($this->dbh) . ') ' . mysql_error($this->dbh) : 'Codebase MySQL error: Could not connect to server.'; |
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149 | App::logMsg($mysql_error_msg, LOG_EMERG, __FILE__, __LINE__); |
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150 | |
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151 | // Print helpful or pretty error? |
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152 | if ($this->getParam('db_debug')) { |
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153 | echo $mysql_error_msg . "\n"; |
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154 | } else { |
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155 | echo _("This page is temporarily unavailable. It should be back up in a few minutes."); |
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156 | } |
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157 | |
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158 | // Die or continue without connection? |
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159 | if ($this->getParam('db_die_on_failure')) { |
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160 | echo "\n\n<!-- Script execution stopped out of embarrassment. -->"; |
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161 | die; |
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162 | } else { |
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163 | return false; |
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164 | } |
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165 | } |
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166 | |
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167 | // DB connection success! |
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168 | $this->_connected = true; |
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169 | |
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170 | // Tell MySQL what character set we're useing. Available only on MySQL verions > 4.01.01. |
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171 | $this->query("/*!40101 SET NAMES '" . $this->mysql_character_sets[strtolower(App::getParam('character_set'))] . "' */"); |
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172 | |
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173 | return true; |
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174 | } |
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175 | |
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176 | /** |
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177 | * Close db connection. |
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178 | * |
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179 | * @access public |
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180 | * @author Quinn Comendant <quinn@strangecode.com> |
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181 | * @since 28 Aug 2005 14:32:01 |
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182 | */ |
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183 | function close() |
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184 | { |
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185 | if (!isset($this) || !is_a($this, 'DB') && !is_subclass_of($this, 'DB')) { |
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186 | $this =& DB::getInstance(); |
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187 | } |
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188 | |
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189 | if (!$this->_connected) { |
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190 | return false; |
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191 | } |
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192 | |
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193 | mysql_close($this->dbh); |
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194 | } |
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195 | |
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196 | /** |
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197 | * Return the current database handler. |
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198 | * |
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199 | * @access public |
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200 | * @return resource Current value of $this->dbh. |
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201 | * @author Quinn Comendant <quinn@strangecode.com> |
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202 | * @since 20 Aug 2005 13:50:36 |
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203 | */ |
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204 | function getDBH() |
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205 | { |
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206 | if (!isset($this) || !is_a($this, 'DB') && !is_subclass_of($this, 'DB')) { |
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207 | $this =& DB::getInstance(); |
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208 | } |
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209 | |
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210 | if (!$this->_connected) { |
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211 | return false; |
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212 | } |
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213 | |
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214 | return $this->dbh; |
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215 | } |
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216 | |
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217 | /** |
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218 | * Returns connection status |
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219 | * |
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220 | * @access public |
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221 | * @author Quinn Comendant <quinn@strangecode.com> |
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222 | * @since 28 Aug 2005 14:58:09 |
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223 | */ |
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224 | function isConnected() |
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225 | { |
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226 | return $this->_connected; |
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227 | } |
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228 | |
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229 | /** |
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230 | * Returns a properly escaped string using mysql_real_escape_string() with the current connection's charset. |
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231 | * |
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232 | * @access public |
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233 | * @param string $string Input string to be sent as SQL query. |
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234 | * @return string Escaped string from mysql_real_escape_string() |
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235 | * @author Quinn Comendant <quinn@strangecode.com> |
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236 | * @since 06 Mar 2006 16:41:32 |
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237 | */ |
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238 | function escapeString($string) |
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239 | { |
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240 | if (!isset($this) || !is_a($this, 'DB') && !is_subclass_of($this, 'DB')) { |
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241 | $this =& DB::getInstance(); |
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242 | } |
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243 | return mysql_real_escape_string($string, $this->dbh); |
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244 | } |
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245 | |
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246 | /** |
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247 | * A wrapper for mysql_query. Allows us to set the database link_identifier, |
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248 | * to trap errors and ease debugging. |
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249 | * |
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250 | * @param string $query The SQL query to execute |
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251 | * @param bool $debug If true, prints debugging info |
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252 | * @return resource Query identifier |
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253 | */ |
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254 | function query($query, $debug=false) |
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255 | { |
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256 | static $_query_count = 0; |
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257 | |
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258 | if (!isset($this) || !is_a($this, 'DB') && !is_subclass_of($this, 'DB')) { |
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259 | $this =& DB::getInstance(); |
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260 | } |
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261 | |
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262 | if (!$this->_connected) { |
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263 | return false; |
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264 | } |
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265 | |
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266 | $_query_count++; |
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267 | $debugqry = preg_replace("/\n[\t ]+/", "\n", $query); |
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268 | if ($this->getParam('db_always_debug') || $debug) { |
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269 | echo "<!-- ----------------- Query $_query_count ---------------------\n$debugqry\n-->\n"; |
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270 | } |
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271 | |
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272 | // Execute! |
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273 | $qid = mysql_query($query, $this->dbh); |
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274 | |
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275 | // Error checking. |
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276 | if (!$qid || mysql_error($this->dbh)) { |
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277 | if ($this->getParam('db_debug')) { |
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278 | echo '<pre style="padding:2em; background:#ddd; font:9px monaco;">' . wordwrap(mysql_error($this->dbh)) . '<hr>' . htmlspecialchars($debugqry) . '</pre>'; |
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279 | } else { |
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280 | echo _("This page is temporarily unavailable. It should be back up in a few minutes."); |
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281 | } |
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282 | App::logMsg(sprintf('MySQL error %s: %s in query: %s', mysql_errno($this->dbh), mysql_error($this->dbh), $debugqry), LOG_EMERG, __FILE__, __LINE__); |
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283 | if ($this->getParam('db_die_on_failure')) { |
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284 | echo "\n\n<!-- Script execution stopped out of embarrassment. -->"; |
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285 | die; |
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286 | } |
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287 | } |
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288 | |
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289 | return $qid; |
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290 | } |
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291 | |
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292 | /** |
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293 | * Loads a list of tables in the current database into an array, and returns |
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294 | * true if the requested table is found. Use this function to enable/disable |
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295 | * funtionality based upon the current available db tables or to dynamically |
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296 | * create tables if missing. |
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297 | * |
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298 | * @param string $table The name of the table to search. |
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299 | * @param bool $strict Get fresh table info (in case DB changed). |
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300 | * @return bool true if given $table exists. |
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301 | */ |
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302 | function tableExists($table, $use_cached_results=true) |
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303 | { |
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304 | if (!isset($this) || !is_a($this, 'DB') && !is_subclass_of($this, 'DB')) { |
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305 | $this =& DB::getInstance(); |
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306 | } |
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307 | |
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308 | if (!$this->_connected) { |
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309 | return false; |
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310 | } |
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311 | |
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312 | if (!isset($this->existing_tables) || !$use_cached_results) { |
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313 | $this->existing_tables = array(); |
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314 | $qid = $this->query("SHOW TABLES"); |
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315 | while (list($row) = mysql_fetch_row($qid)) { |
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316 | $this->existing_tables[] = $row; |
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317 | } |
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318 | } |
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319 | if (in_array($table, $this->existing_tables)) { |
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320 | return true; |
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321 | } else { |
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322 | App::logMsg(sprintf('nonexistent DB table: %s.%s', $this->getParam('db_name'), $table), LOG_ALERT, __FILE__, __LINE__); |
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323 | return false; |
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324 | } |
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325 | } |
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326 | |
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327 | /** |
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328 | * Tests if the given array of columns exists in the specified table. |
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329 | * |
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330 | * @param string $table The name of the table to search. |
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331 | * @param array $columns An array of column names. |
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332 | * @param bool $strict Exact schema match, or are additional fields in the table okay? |
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333 | * @param bool $strict Get fresh table info (in case DB changed). |
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334 | * @return bool true if given $table exists. |
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335 | */ |
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336 | function columnExists($table, $columns, $strict=true, $use_cached_results=true) |
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337 | { |
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338 | if (!isset($this) || !is_a($this, 'DB') && !is_subclass_of($this, 'DB')) { |
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339 | $this =& DB::getInstance(); |
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340 | } |
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341 | |
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342 | if (!$this->_connected) { |
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343 | return false; |
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344 | } |
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345 | |
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346 | // Ensure the table exists. |
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347 | if (!$this->tableExists($table, $use_cached_results)) { |
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348 | return false; |
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349 | } |
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350 | |
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351 | // For single-value columns. |
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352 | if (!is_array($columns)) { |
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353 | $columns = array($columns); |
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354 | } |
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355 | |
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356 | if (!isset($this->table_columns[$table]) || !$use_cached_results) { |
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357 | // Populate and cache array of current columns for this table. |
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358 | $this->table_columns[$table] = array(); |
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359 | $qid = $this->query("DESCRIBE $table"); |
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360 | while ($row = mysql_fetch_row($qid)) { |
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361 | $this->table_columns[$table][] = $row[0]; |
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362 | } |
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363 | } |
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364 | |
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365 | if ($strict) { |
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366 | // Do an exact comparison of table schemas. |
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367 | sort($columns); |
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368 | sort($this->table_columns[$table]); |
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369 | return $this->table_columns[$table] == $columns; |
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370 | } else { |
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371 | // Only check that the specified columns are available in the table. |
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372 | $match_columns = array_intersect($this->table_columns[$table], $columns); |
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373 | sort($columns); |
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374 | sort($match_columns); |
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375 | return $match_columns == $columns; |
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376 | } |
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377 | } |
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378 | |
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379 | /** |
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380 | * Reset cached items. |
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381 | * |
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382 | * @access public |
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383 | * @author Quinn Comendant <quinn@strangecode.com> |
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384 | * @since 28 Aug 2005 22:10:50 |
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385 | */ |
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386 | function resetCache() |
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387 | { |
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388 | $this->existing_tables = null; |
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389 | $this->table_columns = null; |
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390 | } |
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391 | |
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392 | } // End. |
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393 | |
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394 | ?> |
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