Complex classes like Db 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 Db, and based on these observations, apply Extract Interface, too.
1 | <?php |
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22 | class Db |
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23 | { |
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24 | /** |
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25 | * Database handle/connection. |
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26 | * |
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27 | * @var PDO |
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28 | */ |
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29 | protected $pdo; |
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30 | |||
31 | /** |
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32 | * @var string |
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33 | */ |
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34 | protected $dsn; |
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35 | |||
36 | /** |
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37 | * @var string |
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38 | */ |
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39 | protected $username; |
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40 | |||
41 | /** |
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42 | * @var string |
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43 | */ |
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44 | protected $password; |
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45 | |||
46 | /** |
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47 | * @var array |
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48 | */ |
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49 | protected $options; |
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50 | |||
51 | /** |
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52 | * @var bool |
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53 | */ |
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54 | protected $hasActiveTransaction = false; |
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55 | |||
56 | /** |
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57 | * Constructor. |
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58 | * |
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59 | * @param string|PDO $hostDsnOrPdo A MySQL host, a dsn or an existing PDO instance. |
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60 | * @param string|null $username |
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61 | * @param string|null $password |
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62 | * @param string|null $database |
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63 | * @param array $options |
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64 | */ |
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65 | 21 | public function __construct( |
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84 | |||
85 | /** |
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86 | */ |
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87 | 15 | public function connect() |
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125 | |||
126 | /** |
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127 | * @param PDOException $exception |
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128 | * @return bool |
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129 | */ |
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130 | private function isConnectionExceptionCausedByConnection(PDOException $exception) |
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139 | |||
140 | /** |
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141 | * Close the database connection. |
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142 | */ |
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143 | 1 | public function disconnect() |
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147 | |||
148 | /** |
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149 | */ |
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150 | 1 | public function reconnect() |
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155 | |||
156 | /** |
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157 | * Check if database connection is open. |
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158 | * |
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159 | * @return bool |
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160 | */ |
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161 | 16 | public function isConnected() |
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165 | |||
166 | /** |
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167 | * Returns the PDO handle. |
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168 | * |
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169 | * Can be used to gain access to any special PDO methods. |
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170 | * |
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171 | * @return PDO |
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172 | */ |
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173 | 2 | public function getPdo() |
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177 | |||
178 | /** |
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179 | * Creates and executes a PDO statement. |
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180 | * |
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181 | * @param string $sql |
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182 | * @param array $parameters |
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183 | * @return PDOStatement |
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184 | */ |
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185 | 7 | protected function executeQuery($sql, array $parameters = []) |
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199 | |||
200 | /** |
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201 | * Execute an SQL statement and return the number of affected rows. |
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202 | * |
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203 | * @param string $sql |
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204 | * @param array $parameters |
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205 | * @return int The number of rows affected |
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206 | */ |
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207 | 4 | public function exec($sql, array $parameters = []) |
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213 | |||
214 | /** |
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215 | * Execute an SQL statement and return the first row. |
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216 | * |
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217 | * @param string $sql |
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218 | * @param array $parameters |
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219 | * @param bool $indexedKeys |
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220 | * @return array|false |
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221 | */ |
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222 | 1 | public function fetchRow($sql, array $parameters = [], $indexedKeys = false) |
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228 | |||
229 | /** |
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230 | * Execute an SQL statement and return all rows as an array. |
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231 | * |
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232 | * @param string $sql |
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233 | * @param array $parameters |
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234 | * @param bool $indexedKeys |
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235 | * @return array |
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236 | */ |
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237 | 1 | public function fetchRows($sql, array $parameters = [], $indexedKeys = false) |
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243 | |||
244 | /** |
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245 | * Execute an SQL statement and return the first column of the first row. |
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246 | * |
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247 | * @param string $sql |
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248 | * @param array $parameters |
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249 | * @return string|false |
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250 | */ |
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251 | 1 | public function fetchValue($sql, array $parameters = []) |
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257 | |||
258 | /** |
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259 | * Quote a value for a safe use in query (eg. bla'bla -> 'bla''bla'). |
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260 | * |
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261 | * @param mixed $value |
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262 | * @return string |
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263 | */ |
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264 | 1 | public function quote($value) |
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270 | |||
271 | /** |
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272 | * Get id of the last inserted row. |
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273 | * |
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274 | * @return int |
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275 | */ |
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276 | 1 | public function getLastInsertId() |
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282 | |||
283 | /** |
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284 | * Prepare parameters for database use. |
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285 | * |
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286 | * @param array $parameters |
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287 | * @return array |
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288 | */ |
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289 | 7 | protected function prepareParameters(array $parameters = []) |
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290 | { |
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291 | 7 | foreach ($parameters as &$parameterValue) { |
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292 | 6 | if (is_bool($parameterValue)) { |
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293 | 1 | $parameterValue = (int) $parameterValue; |
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294 | 6 | } elseif ($parameterValue instanceof \DateTimeInterface) { |
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295 | 1 | $parameterValue = $parameterValue->format('Y-m-d H:i:s'); |
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296 | 6 | } elseif (!is_scalar($parameterValue) && $parameterValue !== null) { |
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297 | 1 | throw new \InvalidArgumentException( |
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298 | 1 | sprintf('Invalid db parameter type "%s"', gettype($parameterValue)) |
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299 | 1 | ); |
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300 | } |
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301 | 7 | } |
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302 | 6 | unset($parameterValue); |
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303 | |||
304 | 6 | return $parameters; |
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305 | } |
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306 | |||
307 | /** |
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308 | * Begin transaction (turns off autocommit mode). |
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309 | * |
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310 | * @param bool $onlyIfNoActiveTransaction |
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311 | * @return bool |
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312 | */ |
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313 | 4 | public function beginTransaction($onlyIfNoActiveTransaction = false) |
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326 | |||
327 | /** |
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328 | * Commits current active transaction (restores autocommit mode). |
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329 | */ |
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330 | 2 | public function commit() |
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337 | |||
338 | /** |
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339 | * Rolls back current active transaction (restores autocommit mode). |
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340 | */ |
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341 | 2 | public function rollBack() |
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348 | |||
349 | /** |
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350 | * @return bool |
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351 | */ |
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352 | 3 | public function hasActiveTransaction() |
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356 | |||
357 | /** |
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358 | * @param string $table |
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359 | * @param array $data |
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360 | * @return int The number of rows affected |
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361 | */ |
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362 | 1 | public function insert($table, array $data) |
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374 | |||
375 | /** |
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376 | * @param string $table |
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377 | * @param array $data |
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378 | * @param string $whereSql |
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379 | * @param array $whereParameters |
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380 | * @return int The number of rows affected |
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381 | */ |
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382 | 1 | public function update($table, array $data, $whereSql = '', array $whereParameters = []) |
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398 | } |
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399 |