Complex classes like Database often do a lot of different things. To break such a class down, we need to identify a cohesive component within that class. A common approach to find such a component is to look for fields/methods that share the same prefixes, or suffixes. You can also have a look at the cohesion graph to spot any un-connected, or weakly-connected components.
Once you have determined the fields that belong together, you can apply the Extract Class refactoring. If the component makes sense as a sub-class, Extract Subclass is also a candidate, and is often faster.
While breaking up the class, it is a good idea to analyze how other classes use Database, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
||
| 12 | final class Database implements DBInterface{
|
||
| 13 | protected $db; |
||
| 14 | protected $sql; |
||
| 15 | private $key; |
||
| 16 | |||
| 17 | protected $logLocation = 'logs'.DIRECTORY_SEPARATOR; |
||
| 18 | public $logErrors = true; |
||
| 19 | public $logQueries = false; |
||
| 20 | public $displayErrors = false; |
||
| 21 | |||
| 22 | protected $database; |
||
| 23 | protected $cacheEnabled = false; |
||
| 24 | protected $cacheObj; |
||
| 25 | protected $cacheValue; |
||
| 26 | protected $modified = false; |
||
| 27 | |||
| 28 | private $query; |
||
| 29 | private $values = array(); |
||
| 30 | private $prepare = array(); |
||
| 31 | |||
| 32 | /** |
||
| 33 | * Connect to database using PDO connection |
||
| 34 | * @param string $hostname This should be the host of the database e.g. 'localhost' |
||
| 35 | * @param string $username This should be the username for the chosen database |
||
| 36 | * @param string $password This should be the password for the chosen database |
||
| 37 | * @param string $database This should be the database that you wish to connect to |
||
| 38 | * @param string|null $backuphost If you have a replication server set up put the hostname or IP address incase the primary server goes down |
||
| 39 | */ |
||
| 40 | public function __construct($hostname, $username, $password, $database, $backuphost = NULL){
|
||
| 41 | try{
|
||
| 42 | $this->connectToServer($username, $password, $database, $hostname); |
||
| 43 | } |
||
| 44 | catch(\Exception $e){
|
||
| 45 | if($backuphost !== NULL){
|
||
| 46 | $this->connectToServer($username, $password, $database, $backuphost); |
||
| 47 | } |
||
| 48 | $this->error($e); |
||
| 49 | } |
||
| 50 | } |
||
| 51 | |||
| 52 | /** |
||
| 53 | * Closes the PDO database connection when Database object unset |
||
| 54 | */ |
||
| 55 | public function __destruct(){
|
||
| 56 | $this->closeDatabase(); |
||
| 57 | } |
||
| 58 | |||
| 59 | /** |
||
| 60 | * Connect to the database using PDO connection |
||
| 61 | * @param string $username This should be the username for the chosen database |
||
| 62 | * @param string $password This should be the password for the chosen database |
||
| 63 | * @param string $database This should be the database that you wish to connect to |
||
| 64 | * @param string $hostname The hostname for the database |
||
| 65 | */ |
||
| 66 | protected function connectToServer($username, $password, $database, $hostname){
|
||
| 67 | if(!$this->db){
|
||
| 68 | $this->database = $database; |
||
| 69 | $this->db = new PDO('mysql:host='.$hostname.';dbname='.$database, $username, $password, array(PDO::ATTR_ERRMODE => PDO::ERRMODE_EXCEPTION, PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => true, PDO::ATTR_PERSISTENT => true, PDO::ATTR_EMULATE_PREPARES => true));
|
||
| 70 | } |
||
| 71 | } |
||
| 72 | |||
| 73 | /** |
||
| 74 | * Enables the caching and set the caching object to the one provided |
||
| 75 | * @param object $caching This should be class of the type of caching you are using |
||
| 76 | */ |
||
| 77 | public function setCaching($caching){
|
||
| 78 | if(is_object($caching)){
|
||
| 79 | $this->cacheObj = $caching; |
||
| 80 | $this->cacheEnabled = true; |
||
| 81 | } |
||
| 82 | return $this; |
||
| 83 | } |
||
| 84 | |||
| 85 | /** |
||
| 86 | * This query function is used for more advanced SQL queries for which non of the other methods fit |
||
| 87 | * @param string $sql This should be the SQL query which you wish to run |
||
| 88 | * @return array Returns array of results for the query that has just been run |
||
| 89 | */ |
||
| 90 | 1 | public function query($sql, $variables = array(), $cache = true){
|
|
| 91 | try{
|
||
| 92 | 1 | $this->sql = $sql; |
|
| 93 | 1 | $this->query = $this->db->prepare($this->sql); |
|
| 94 | 1 | $this->query->execute($variables); |
|
| 95 | 1 | if(strpos($this->sql, 'SELECT') !== false){
|
|
| 96 | 1 | return $this->query->fetchAll(PDO::FETCH_ASSOC); |
|
| 97 | } |
||
| 98 | } |
||
| 99 | catch(\Exception $e){
|
||
| 100 | $this->error($e); |
||
| 101 | } |
||
| 102 | } |
||
| 103 | |||
| 104 | /** |
||
| 105 | * Returns a single record for a select query for the chosen table |
||
| 106 | * @param string $table This should be the table you wish to select the values from |
||
| 107 | * @param array $where Should be the field names and values you wish to use as the where query e.g. array('fieldname' => 'value', 'fieldname2' => 'value2', etc).
|
||
| 108 | * @param string|array $fields This should be the records you wis to select from the table. It should be either set as '*' which is the default or set as an array in the following format array('field', 'field2', 'field3', etc).
|
||
| 109 | * @param array $order This is the order you wish the results to be ordered in should be formatted as follows array('fieldname' => 'ASC') or array("'fieldname', 'fieldname2'" => 'DESC')
|
||
| 110 | * @param boolean $cache If the query should be cached or loaded from cache set to true else set to false |
||
| 111 | * @return array Returns a single table record as the standard array when running SQL queries |
||
| 112 | */ |
||
| 113 | public function select($table, $where = array(), $fields = '*', $order = array(), $cache = true){
|
||
| 116 | |||
| 117 | /** |
||
| 118 | * Returns a multidimensional array of the results from the selected table given the given parameters |
||
| 119 | * @param string $table This should be the table you wish to select the values from |
||
| 120 | * @param array $where Should be the field names and values you wish to use as the where query e.g. array('fieldname' => 'value', 'fieldname2' => 'value2', etc).
|
||
| 121 | * @param string|array $fields This should be the records you wis to select from the table. It should be either set as '*' which is the default or set as an array in the following format array('field', 'field2', 'field3', etc).
|
||
| 122 | * @param array $order This is the order you wish the results to be ordered in should be formatted as follows array('fieldname' => 'ASC') or array("'fieldname', 'fieldname2'" => 'DESC')
|
||
| 123 | * @param integer|array $limit The number of results you want to return 0 is default and returns all results, else should be formated either as a standard integer or as an array as the start and end values e.g. array(0 => 150) |
||
| 124 | * @param boolean $cache If the query should be cached or loaded from cache set to true else set to false |
||
| 125 | * @return array Returns a multidimensional array with the chosen fields from the table |
||
| 126 | */ |
||
| 127 | public function selectAll($table, $where = array(), $fields = '*', $order = array(), $limit = 0, $cache = true){
|
||
| 128 | $this->buildSelectQuery($table, $where, $fields, $order, $limit); |
||
| 129 | $result = $this->executeQuery($cache); |
||
| 130 | if(!$result){
|
||
| 131 | if($limit === 1){$result = $this->query->fetch(PDO::FETCH_ASSOC);} // Reduce the memory usage if only one record and increase performance
|
||
| 132 | else{$result = $this->query->fetchAll(PDO::FETCH_ASSOC);}
|
||
| 133 | if($cache && $this->cacheEnabled){$this->setCache($this->key, $result);}
|
||
| 134 | } |
||
| 135 | return $result; |
||
| 136 | } |
||
| 137 | |||
| 138 | /** |
||
| 139 | * Returns a single column value for a given query |
||
| 140 | * @param string $table This should be the table you wish to select the values from |
||
| 141 | * @param array $where Should be the field names and values you wish to use as the where query e.g. array('fieldname' => 'value', 'fieldname2' => 'value2', etc).
|
||
| 142 | * @param array $fields This should be the records you wis to select from the table. It should be either set as '*' which is the default or set as an array in the following format array('field', 'field2', 'field3', etc).
|
||
| 143 | * @param int $colNum This should be the column number you wish to get (starts at 0) |
||
| 144 | * @param array $order This is the order you wish the results to be ordered in should be formatted as follows array('fieldname' => 'ASC') or array("'fieldname', 'fieldname2'" => 'DESC') so it can be done in both directions
|
||
| 145 | * @param boolean $cache If the query should be cached or loaded from cache set to true else set to false |
||
| 146 | * @return mixed If a result is found will return the value of the colum given else will return false |
||
| 147 | */ |
||
| 148 | public function fetchColumn($table, $where = array(), $fields = '*', $colNum = 0, $order = array(), $cache = true){
|
||
| 149 | $this->buildSelectQuery($table, $where, $fields, $order, 1); |
||
| 150 | $result = $this->executeQuery($cache); |
||
| 151 | if(!$result){
|
||
| 152 | $result = $this->query->fetchColumn(intval($colNum)); |
||
| 153 | if($cache && $this->cacheEnabled){$this->setCache($this->key, $result);}
|
||
| 154 | } |
||
| 155 | return $result; |
||
| 156 | } |
||
| 157 | |||
| 158 | /** |
||
| 159 | * Inserts into database using the prepared PDO statements |
||
| 160 | * @param string $table This should be the table you wish to insert the values into |
||
| 161 | * @param array $records This should be the field names and values in the format of array('fieldname' => 'value', 'fieldname2' => 'value2', etc.)
|
||
| 162 | * @return boolean If data is inserted returns true else returns false |
||
| 163 | */ |
||
| 164 | public function insert($table, $records){
|
||
| 171 | |||
| 172 | /** |
||
| 173 | * Updates values in a database using the provide variables |
||
| 174 | * @param string $table This should be the table you wish to update the values for |
||
| 175 | * @param array $records This should be the field names and new values in the format of array('fieldname' => 'newvalue', 'fieldname2' => 'newvalue2', etc.)
|
||
| 176 | * @param array $where Should be the field names and values you wish to update in the form of an array e.g. array('fieldname' => 'value', 'fieldname2' => 'value2', etc).
|
||
| 177 | * @param int $limit The number of results you want to return 0 is default and will update all results that match the query, else should be formated as a standard integer |
||
| 178 | * @return boolean Returns true if update is successful else returns false |
||
| 179 | */ |
||
| 180 | public function update($table, $records, $where = array(), $limit = 0){
|
||
| 185 | |||
| 186 | /** |
||
| 187 | * Deletes records from the given table based on the variables given |
||
| 188 | * @param string $table This should be the table you wish to delete the records from |
||
| 189 | * @param array $where This should be an array of for the where statement |
||
| 190 | * @param int $limit The number of results you want to return 0 is default and will delete all results that match the query, else should be formated as a standard integer |
||
| 191 | */ |
||
| 192 | public function delete($table, $where, $limit = 0){
|
||
| 197 | |||
| 198 | /** |
||
| 199 | * Count the number of return results |
||
| 200 | * @param string $table The table you wish to count the result of |
||
| 201 | * @param array $where Should be the field names and values you wish to use as the where query e.g. array('fieldname' => 'value', 'fieldname2' => 'value2', etc).
|
||
| 202 | * @param boolean $cache If the query should be cached or loaded from cache set to true else set to false |
||
| 203 | * @return int Returns the number of results |
||
| 204 | */ |
||
| 205 | public function count($table, $where = array(), $cache = true){
|
||
| 206 | $this->sql = sprintf("SELECT count(*) FROM `%s`%s;", $table, $this->where($where));
|
||
| 207 | $this->key = md5($this->database.$this->sql.serialize($this->values)); |
||
| 208 | |||
| 209 | $result = $this->executeQuery($cache); |
||
| 210 | if(!$result){
|
||
| 211 | $result = $this->query->fetchColumn(); |
||
| 212 | if($cache && $this->cacheEnabled){$this->setCache($this->key, $result);}
|
||
| 213 | } |
||
| 214 | return $result; |
||
| 215 | } |
||
| 216 | |||
| 217 | /** |
||
| 218 | * Truncates a given table from the selected database so there are no values in the table |
||
| 219 | * @param string $table This should be the table you wish to truncate |
||
| 220 | * @return boolean If the table is emptied returns true else returns false |
||
| 221 | */ |
||
| 222 | public function truncate($table){
|
||
| 232 | |||
| 233 | /** |
||
| 234 | * Returns the number of rows for the last query sent |
||
| 235 | * @return int Returns the number of rows for the last query |
||
| 236 | */ |
||
| 237 | public function numRows(){
|
||
| 243 | |||
| 244 | /** |
||
| 245 | * Returns the number of rows for the last query sent (Looks a the numRows() function just added incase of habbit) |
||
| 246 | * @return int Returns the number of rows for the last query |
||
| 247 | */ |
||
| 248 | public function rowCount(){
|
||
| 251 | |||
| 252 | /** |
||
| 253 | * Returns the ID of the last record last inserted |
||
| 254 | * @param string $name This should be the name of the sequence object you wish to retrieve |
||
| 255 | * @return int|string Returns the last inserted ID of the last insert item if $name is null else returns string with sequenced object |
||
| 256 | */ |
||
| 257 | public function lastInsertId($name = null) {
|
||
| 260 | |||
| 261 | /** |
||
| 262 | * Returns the index of the given table or tables within the database |
||
| 263 | * @param string|array $table Table can wither be a standard string with a single table name or an array with multiple table names |
||
| 264 | * @return array Returns the table index for the selected table as an array |
||
| 265 | */ |
||
| 266 | public function fulltextIndex($table){
|
||
| 267 | $fieldlist = array(); |
||
| 268 | if(is_array($table)){
|
||
| 269 | foreach($table as $name){
|
||
| 270 | $fieldlist[$name] = $this->fulltextIndex($name); |
||
| 271 | } |
||
| 272 | }else{
|
||
| 273 | try{
|
||
| 274 | $this->sql = sprintf("SHOW INDEX FROM %s;", $table);
|
||
| 275 | $this->query = $this->db->exec($this->sql); |
||
| 276 | } |
||
| 277 | catch(\Exception $e){
|
||
| 278 | $this->error($e); |
||
| 279 | } |
||
| 280 | |||
| 281 | while($index = $this->query->fetch(PDO::FETCH_ASSOC)){
|
||
| 282 | if($index['Index_type'] == 'FULLTEXT' && $index['Key_name'] == 'fulltext'){
|
||
| 283 | $fieldlist[] = $index['Column_name']; |
||
| 284 | } |
||
| 285 | } |
||
| 286 | } |
||
| 287 | return $fieldlist; |
||
| 288 | } |
||
| 289 | |||
| 290 | /** |
||
| 291 | * Returns the server version information |
||
| 292 | */ |
||
| 293 | public function serverVersion(){
|
||
| 296 | |||
| 297 | /** |
||
| 298 | * Displays the error massage which occurs |
||
| 299 | * @param \Exception $error This should be an instance of Exception |
||
| 300 | */ |
||
| 301 | private function error($error){
|
||
| 302 | if($this->logErrors){
|
||
| 303 | $file = $this->logLocation.'db-errors.txt'; |
||
| 304 | $current = file_get_contents($file); |
||
| 305 | $current .= date('d/m/Y H:i:s')." ERROR: ".$error->getMessage()." on ".$this->sql."\n";
|
||
| 306 | file_put_contents($file, $current); |
||
| 307 | } |
||
| 308 | if($this->displayErrors){
|
||
| 309 | die('ERROR: '.$error->getMessage().' on '.$this->sql);
|
||
| 310 | } |
||
| 311 | } |
||
| 312 | |||
| 313 | /** |
||
| 314 | * Writes all queries to a log file |
||
| 315 | */ |
||
| 316 | public function writeQueryToLog(){
|
||
| 322 | |||
| 323 | /** |
||
| 324 | * Closes the PDO database connection by setting the connection to NULL |
||
| 325 | */ |
||
| 326 | public function closeDatabase(){
|
||
| 327 | $this->db = null; |
||
| 328 | } |
||
| 329 | |||
| 330 | /** |
||
| 331 | * Build the SQL query but doesn't execute it |
||
| 332 | * @param string $table This should be the table you wish to select the values from |
||
| 333 | * @param array $where Should be the field names and values you wish to use as the where query e.g. array('fieldname' => 'value', 'fieldname2' => 'value2', etc).
|
||
| 334 | * @param string|array $fields This should be the records you wis to select from the table. It should be either set as '*' which is the default or set as an array in the following format array('field', 'field2', 'field3', etc).
|
||
| 335 | * @param array $order This is the order you wish the results to be ordered in should be formatted as follows array('fieldname' => 'ASC') or array("'fieldname', 'fieldname2'" => 'DESC') so it can be done in both directions
|
||
| 336 | * @param integer|array $limit The number of results you want to return 0 is default and returns all results, else should be formated either as a standard integer or as an array as the start and end values e.g. array(0 => 150) |
||
| 337 | */ |
||
| 338 | protected function buildSelectQuery($table, $where = array(), $fields = '*', $order = array(), $limit = 0){
|
||
| 339 | if(is_array($fields)){
|
||
| 340 | $selectfields = array(); |
||
| 341 | foreach($fields as $field => $value){
|
||
| 342 | $selectfields[] = sprintf("`%s`", $value);
|
||
| 343 | } |
||
| 344 | $fieldList = implode(', ', $selectfields);
|
||
| 345 | } |
||
| 346 | else{$fieldList = '*';}
|
||
| 347 | |||
| 348 | $this->sql = sprintf("SELECT %s FROM `%s`%s%s%s;", $fieldList, $table, $this->where($where), $this->orderBy($order), $this->limit($limit));
|
||
| 349 | $this->key = md5($this->database.$this->sql.serialize($this->values)); |
||
| 350 | } |
||
| 351 | |||
| 352 | /** |
||
| 353 | * Execute the current query if no cache value is available |
||
| 354 | * @param boolean $cache If the cache should be checked for the checked for the values of the query set to true else set to false |
||
| 355 | * @return mixed If a cached value exists will be returned else if cache is not checked and query is executed will not return anything |
||
| 356 | */ |
||
| 357 | protected function executeQuery($cache = true){
|
||
| 371 | |||
| 372 | /** |
||
| 373 | * This outputs the SQL where query based on a given array |
||
| 374 | * @param array $where This should be an array that you wish to create the where query for in the for array('field1' => 'test') or array('field1' => array('>=', 0))
|
||
| 375 | * @return string|false If the where query is an array will return the where string and set the values else returns false if no array sent |
||
| 376 | */ |
||
| 377 | private function where($where){
|
||
| 378 | if(is_array($where)){
|
||
| 379 | $wherefields = array(); |
||
| 380 | foreach($where as $what => $value){
|
||
| 381 | if(is_array($value)){
|
||
| 382 | if($value[1] == 'NULL' || $value[1] == 'NOT NULL'){
|
||
| 383 | $wherefields[] = sprintf("`%s` %s %s", $what, addslashes($value[0]), $value[1]);
|
||
| 384 | } |
||
| 385 | else{
|
||
| 386 | $wherefields[] = sprintf("`%s` %s ?", $what, addslashes($value[0]));
|
||
| 387 | $this->values[] = $value[1]; |
||
| 388 | } |
||
| 389 | } |
||
| 390 | else{
|
||
| 391 | $wherefields[] = sprintf("`%s` = ?", $what);
|
||
| 392 | $this->values[] = $value; |
||
| 393 | } |
||
| 394 | } |
||
| 395 | if(!empty($wherefields)){
|
||
| 396 | return " WHERE ".implode(' AND ', $wherefields);
|
||
| 397 | } |
||
| 398 | } |
||
| 399 | return false; |
||
| 400 | } |
||
| 401 | |||
| 402 | /** |
||
| 403 | * Sets the order sting for the SQL query based on an array or string |
||
| 404 | * @param array|string $order This should be either set to array('fieldname' => 'ASC/DESC') or RAND()
|
||
| 405 | * @return string|false If the SQL query has an valid order by will return a string else returns false |
||
| 406 | */ |
||
| 407 | private function orderBy($order){
|
||
| 408 | if(is_array($order)){
|
||
| 409 | foreach($order as $fieldorder => $fieldvalue){
|
||
| 410 | return sprintf(" ORDER BY `%s` %s", $fieldorder, strtoupper($fieldvalue));
|
||
| 411 | } |
||
| 412 | } |
||
| 413 | elseif($order == 'RAND()'){
|
||
| 414 | return " ORDER BY RAND()"; |
||
| 415 | } |
||
| 416 | return false; |
||
| 417 | } |
||
| 418 | |||
| 419 | /** |
||
| 420 | * Build the field list for the query |
||
| 421 | * @param array $records This should be an array listing all of the fields |
||
| 422 | * @param boolean $insert If this is an insert statement should be set to true to create the correct amount of queries for the prepared statement |
||
| 423 | * @return string The fields list will be returned as a string to insert into the SQL query |
||
| 424 | */ |
||
| 425 | private function fields($records, $insert = false){
|
||
| 426 | $fields = array(); |
||
| 427 | |||
| 428 | foreach($records as $field => $value){
|
||
| 429 | if($insert === true){
|
||
| 430 | $fields[] = sprintf("`%s`", $field);
|
||
| 431 | $this->prepare[] = '?'; |
||
| 432 | } |
||
| 433 | else{
|
||
| 434 | $fields[] = sprintf("`%s` = ?", $field);
|
||
| 435 | } |
||
| 436 | $this->values[] = $value; |
||
| 437 | } |
||
| 438 | return implode(', ', $fields);
|
||
| 439 | } |
||
| 440 | |||
| 441 | /** |
||
| 442 | * Returns the limit SQL for the current query as a string |
||
| 443 | * @param integer|array $limit This should either be set as an integer or should be set as an array with a start and end value |
||
| 444 | * @return string|false Will return the LIMIT string for the current query if it is valid else returns false |
||
| 445 | */ |
||
| 446 | private function limit($limit = 0){
|
||
| 447 | if(is_array($limit)){
|
||
| 448 | foreach($limit as $start => $end){
|
||
| 449 | return " LIMIT ".(int)$start.", ".(int)$end; |
||
| 450 | } |
||
| 451 | } |
||
| 452 | elseif((int)$limit > 0){
|
||
| 453 | return " LIMIT ".(int)$limit; |
||
| 454 | } |
||
| 455 | return false; |
||
| 456 | } |
||
| 457 | |||
| 458 | |||
| 459 | /** |
||
| 460 | * Set the cache with a key and value |
||
| 461 | * @param string $key The unique key to store the value against |
||
| 462 | * @param mixed $value The value of the MYSQL query |
||
| 463 | */ |
||
| 464 | public function setCache($key, $value){
|
||
| 465 | if($this->cacheEnabled){
|
||
| 466 | $this->cacheObj->save($key, $value); |
||
| 467 | } |
||
| 468 | } |
||
| 469 | |||
| 470 | /** |
||
| 471 | * Get the results for a given key |
||
| 472 | * @param string $key The unique key to check for stored variables |
||
| 473 | * @return mixed Returned the cached results from |
||
| 474 | */ |
||
| 475 | public function getCache($key){
|
||
| 482 | |||
| 483 | /** |
||
| 484 | * Clears the cache |
||
| 485 | */ |
||
| 486 | public function flushDB(){
|
||
| 489 | } |
||
| 490 |