Duplicate code is one of the most pungent code smells. A rule that is often used is to re-structure code once it is duplicated in three or more places.
Common duplication problems, and corresponding solutions are:
Complex classes like DatabaseHelper 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 DatabaseHelper, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 21 | class DatabaseHelper extends AbstractHelper  | 
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| 22 | { | 
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| 23 | /**  | 
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| 24 | * @var array|DbSettings  | 
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| 25 | */  | 
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| 26 | protected $dbSettings = null;  | 
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| 27 | |||
| 28 | /**  | 
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| 29 | * @var bool  | 
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| 30 | * @deprecated since 1.97.9, use $dbSettings->isSocketConnect()  | 
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| 31 | */  | 
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| 32 | protected $isSocketConnect = false;  | 
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| 33 | |||
| 34 | /**  | 
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| 35 | * @var PDO  | 
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| 36 | */  | 
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| 37 | protected $_connection = null;  | 
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| 38 | |||
| 39 | /**  | 
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| 40 | * @var array  | 
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| 41 | */  | 
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| 42 | protected $_tables;  | 
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| 43 | |||
| 44 | /**  | 
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| 45 | * @param OutputInterface $output  | 
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| 46 | *  | 
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| 47 | * @throws RuntimeException  | 
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| 48 | * @return void  | 
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| 49 | */  | 
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| 50 | public function detectDbSettings(OutputInterface $output)  | 
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| 74 | |||
| 75 | /**  | 
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| 76 | * Connects to the database without initializing magento  | 
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| 77 | *  | 
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| 78 | * @param OutputInterface $output = null  | 
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| 79 | *  | 
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| 80 | * @return PDO  | 
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| 81 | */  | 
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| 82 | public function getConnection(OutputInterface $output = null)  | 
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| 90 | |||
| 91 | /**  | 
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| 92 | * Creates a PDO DSN for the adapter from $this->_config settings.  | 
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| 93 | *  | 
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| 94 | * @see Zend_Db_Adapter_Pdo_Abstract  | 
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| 95 | * @return string  | 
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| 96 | */  | 
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| 97 | public function dsn()  | 
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| 101 | |||
| 102 | /**  | 
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| 103 | * Check whether current mysql user has $privilege privilege  | 
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| 104 | *  | 
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| 105 | * @param string $privilege  | 
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| 106 | *  | 
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| 107 | * @return bool  | 
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| 108 | */  | 
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| 109 | public function mysqlUserHasPrivilege($privilege)  | 
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| 124 | |||
| 125 | /**  | 
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| 126 | * @return string  | 
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| 127 | */  | 
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| 128 | public function getMysqlClientToolConnectionString()  | 
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| 132 | |||
| 133 | /**  | 
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| 134 | * Get mysql variable value  | 
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| 135 | *  | 
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| 136 | * @param string $variable  | 
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| 137 | *  | 
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| 138 | * @return bool|array returns array on success, false on failure  | 
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| 139 | */  | 
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| 140 | public function getMysqlVariableValue($variable)  | 
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| 154 | |||
| 155 | /**  | 
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| 156 | * obtain mysql variable value from the database connection.  | 
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| 157 | *  | 
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| 158 | * in difference to @see getMysqlVariableValue(), this method allows to specify the type of the variable as well  | 
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| 159 | * as to use any variable identifier even such that need quoting.  | 
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| 160 | *  | 
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| 161 | * @param string $name mysql variable name  | 
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| 162 |      * @param string $type [optional] variable type, can be a system variable ("@@", default) or a session variable | 
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| 163 |      *                     ("@"). | 
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| 164 | *  | 
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| 165 | * @return string variable value, null if variable was not defined  | 
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| 166 | * @throws RuntimeException in case a system variable is unknown (SQLSTATE[HY000]: 1193: Unknown system variable  | 
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| 167 | * 'nonexistent')  | 
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| 168 | */  | 
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| 169 | public function getMysqlVariable($name, $type = null)  | 
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| 202 | |||
| 203 | /**  | 
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| 204 | * @param array $commandConfig  | 
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| 205 | *  | 
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| 206 | * @throws RuntimeException  | 
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| 207 | * @return array  | 
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| 208 | */  | 
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| 209 | public function getTableDefinitions(array $commandConfig)  | 
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| 249 | |||
| 250 | /**  | 
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| 251 | * @param array $list to resolve  | 
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| 252 | * @param array $definitions from to resolve  | 
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| 253 | * @param array $resolved Which definitions where already resolved -> prevent endless loops  | 
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| 254 | *  | 
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| 255 | * @return array  | 
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| 256 | * @throws RuntimeException  | 
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| 257 | */  | 
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| 258 | public function resolveTables(array $list, array $definitions = array(), array $resolved = array())  | 
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| 310 | |||
| 311 | /**  | 
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| 312 | * @param array $definitions  | 
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| 313 | * @param string $code  | 
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| 314 | * @return array tables  | 
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| 315 | */  | 
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| 316 | private function resolveRetrieveDefinitionsTablesByCode(array $definitions, $code)  | 
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| 331 | |||
| 332 | /**  | 
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| 333 | * @param array|null $carry [optional]  | 
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| 334 | * @param $item [optional]  | 
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| 335 | * @return array  | 
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| 336 | * @throws InvalidArgumentException if item is not an array or string  | 
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| 337 | */  | 
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| 338 | private function resolveTablesArray(array $carry = null, $item = null)  | 
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| 354 | |||
| 355 | /**  | 
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| 356 | * Get list of database tables  | 
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| 357 | *  | 
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| 358 | * @param bool $withoutPrefix [optional] remove prefix from the returned table names. prefix is obtained from  | 
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| 359 | * magento database configuration. defaults to false.  | 
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| 360 | *  | 
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| 361 | * @return array  | 
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| 362 | * @throws RuntimeException  | 
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| 363 | */  | 
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| 364 | public function getTables($withoutPrefix = null)  | 
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| 405 | |||
| 406 | /**  | 
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| 407 | * throw a runtime exception and provide error info for the statement if available  | 
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| 408 | *  | 
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| 409 | * @param PDOStatement $statement  | 
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| 410 | * @param string $message  | 
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| 411 | *  | 
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| 412 | * @throws RuntimeException  | 
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| 413 | */  | 
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| 414 | private function throwRuntimeException(PDOStatement $statement, $message = "")  | 
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| 428 | |||
| 429 | /**  | 
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| 430 | * quote a string so that it is safe to use in a LIKE  | 
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| 431 | *  | 
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| 432 | * @param string $string  | 
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| 433 | * @param string $escape character - single us-ascii character  | 
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| 434 | *  | 
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| 435 | * @return string  | 
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| 436 | */  | 
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| 437 | private function quoteLike($string, $escape = '=')  | 
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| 447 | |||
| 448 | /**  | 
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| 449 | * Get list of db tables status  | 
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| 450 | *  | 
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| 451 | * @param bool $withoutPrefix  | 
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| 452 | *  | 
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| 453 | * @return array  | 
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| 454 | */  | 
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| 455 | public function getTablesStatus($withoutPrefix = false)  | 
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| 483 | |||
| 484 | /**  | 
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| 485 | * @param OutputInterface $output [optional]  | 
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| 486 | *  | 
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| 487 | * @return array|DbSettings  | 
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| 488 | */  | 
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| 489 | public function getDbSettings(OutputInterface $output = null)  | 
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| 505 | |||
| 506 | /**  | 
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| 507 | * @return boolean  | 
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| 508 | */  | 
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| 509 | public function getIsSocketConnect()  | 
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| 513 | |||
| 514 | /**  | 
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| 515 | * Returns the canonical name of this helper.  | 
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| 516 | *  | 
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| 517 | * @return string The canonical name  | 
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| 518 | *  | 
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| 519 | * @api  | 
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| 520 | */  | 
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| 521 | public function getName()  | 
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| 525 | |||
| 526 | /**  | 
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| 527 | * @param OutputInterface $output  | 
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| 528 | */  | 
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| 529 | View Code Duplication | public function dropDatabase($output)  | 
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| 536 | |||
| 537 | /**  | 
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| 538 | * @param OutputInterface $output  | 
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| 539 | */  | 
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| 540 | public function dropTables($output)  | 
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| 553 | |||
| 554 | /**  | 
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| 555 | * @param OutputInterface $output  | 
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| 556 | */  | 
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| 557 | View Code Duplication | public function createDatabase($output)  | 
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| 564 | |||
| 565 | /**  | 
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| 566 | * @param string $command example: 'VARIABLES', 'STATUS'  | 
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| 567 | * @param string|null $variable [optional]  | 
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| 568 | *  | 
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| 569 | * @return array  | 
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| 570 | */  | 
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| 571 | private function runShowCommand($command, $variable = null)  | 
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| 600 | |||
| 601 | /**  | 
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| 602 | * @param string|null $variable [optional]  | 
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| 603 | *  | 
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| 604 | * @return array  | 
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| 605 | */  | 
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| 606 | public function getGlobalVariables($variable = null)  | 
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| 610 | |||
| 611 | /**  | 
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| 612 | * @param string|null $variable [optional]  | 
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| 613 | *  | 
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| 614 | * @return array  | 
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| 615 | */  | 
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| 616 | public function getGlobalStatus($variable = null)  | 
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| 620 | |||
| 621 | /**  | 
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| 622 | * @return Application|BaseApplication  | 
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| 623 | */  | 
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| 624 | private function getApplication()  | 
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| 636 | |||
| 637 | /**  | 
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| 638 | * small helper method to obtain an object of type OutputInterface  | 
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| 639 | *  | 
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| 640 | * @param OutputInterface|null $output  | 
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| 641 | *  | 
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| 642 | * @return OutputInterface  | 
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| 643 | */  | 
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| 644 | private function fallbackOutput(OutputInterface $output = null)  | 
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| 662 | }  | 
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| 663 | 
This check marks implicit conversions of arrays to boolean values in a comparison. While in PHP an empty array is considered to be equal (but not identical) to false, this is not always apparent.
Consider making the comparison explicit by using
empty(..)or! empty(...)instead.