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 DatabaseQuery 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 DatabaseQuery, and based on these observations, apply Extract Interface, too.
1 | <?php |
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20 | class DatabaseQuery implements DatabaseQueryInterface |
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21 | { |
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22 | //Inject the inflector trait, file upload trait |
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23 | use Inflector, Upload; |
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24 | |||
25 | /** |
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26 | * connect Setup database connection |
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27 | */ |
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28 | protected static function connect() |
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32 | |||
33 | /** |
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34 | * stripclassName() |
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35 | * |
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36 | * @return string |
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37 | */ |
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38 | public static function stripclassName() |
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45 | |||
46 | /** |
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47 | * Get the table name if defined in the model |
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48 | * |
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49 | * @return string |
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50 | */ |
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51 | public function tableName() |
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55 | |||
56 | /** |
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57 | * Get the fields to be fillables defined in the model |
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58 | * |
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59 | * @return string |
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60 | */ |
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61 | public function fields() |
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71 | |||
72 | /** |
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73 | * getClassName() |
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74 | * |
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75 | * @return string |
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76 | */ |
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77 | public function getClassName() |
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81 | |||
82 | /** |
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83 | * getTableName() |
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84 | * |
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85 | * @return string |
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86 | */ |
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87 | protected function getTableName($connection) |
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91 | |||
92 | |||
93 | /** |
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94 | * sanitize(argument) Removes unwanted characters |
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95 | * |
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96 | * @param $value |
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97 | * |
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98 | * @return string |
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99 | */ |
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100 | protected static function sanitize($value) |
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106 | |||
107 | /** |
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108 | * checkConnection |
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109 | * |
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110 | * @param $con |
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111 | * |
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112 | * @return string |
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113 | */ |
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114 | protected static function checkConnection($con) |
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118 | |||
119 | /** |
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120 | * checkTableExist Check if table already in the database |
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121 | * |
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122 | * @param $tablename |
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123 | * @param $con |
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124 | * |
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125 | * @return bool |
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126 | */ |
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127 | View Code Duplication | public function checkTableExist($table, $con=NULL) |
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136 | |||
137 | /** |
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138 | * checkTableName Return the table name |
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139 | * |
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140 | * @param $tablename |
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141 | * @param $con |
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142 | * |
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143 | * @return string |
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144 | */ |
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145 | View Code Duplication | protected static function checkTableName($tableName, $con=NULL) |
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156 | |||
157 | /** |
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158 | * checkColumn Check if column exist in table |
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159 | * |
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160 | * @param $tableName |
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161 | * @param $columnName |
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162 | * @param $con |
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163 | * |
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164 | * @return string |
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165 | */ |
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166 | protected static function checkColumn($tableName, $columnName, $con=NULL) |
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178 | |||
179 | /** |
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180 | * Get the variables declared in the Model |
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181 | * |
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182 | * @return Array |
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183 | */ |
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184 | protected static function getParentClassVar() |
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188 | |||
189 | /** |
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190 | * Get the difference in variables between model and column definition |
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191 | * |
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192 | * @param $getClassVars |
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193 | * |
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194 | * @return Array |
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195 | */ |
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196 | protected static function getColumns($getClassVars) |
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200 | |||
201 | /** |
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202 | * buildColumn Build the column name |
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203 | * |
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204 | * @param $data |
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205 | * |
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206 | * @return string |
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207 | */ |
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208 | protected static function buildColumn($getClassVars) |
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225 | |||
226 | /** |
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227 | * buildValues Build the column values |
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228 | * |
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229 | * @param $data |
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230 | * |
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231 | * @return string |
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232 | */ |
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233 | View Code Duplication | protected static function buildValues($getClassVars) |
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249 | |||
250 | /** |
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251 | * buildClause Build the clause value |
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252 | * |
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253 | * @param $data |
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254 | * |
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255 | * @return string |
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256 | */ |
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257 | View Code Duplication | protected static function buildClause($tableName, $data) |
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275 | |||
276 | /** |
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277 | * selectAllQuery |
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278 | * |
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279 | * @return string |
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280 | */ |
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281 | public static function selectAllQuery($tableName, $field) |
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285 | |||
286 | /** |
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287 | * whereAndClause |
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288 | * |
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289 | * @return string |
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290 | */ |
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291 | public static function whereAndClause($tableName, $data, $condition) |
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314 | |||
315 | /** |
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316 | * selectQuery |
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317 | * |
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318 | * @return string |
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319 | */ |
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320 | public static function selectQuery($tableName, $fields, $data, $condition, $connection) |
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341 | |||
342 | /** |
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343 | * insertQuery |
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344 | * |
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345 | * @return string |
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346 | */ |
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347 | public function insertQuery($tableName) |
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357 | |||
358 | /** |
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359 | * updateQuery |
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360 | * |
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361 | * @return string |
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362 | */ |
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363 | public function updateQuery($tableName) |
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373 | |||
374 | /** |
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375 | * query($query, $dbCOnnection) |
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376 | * Raw sql query |
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377 | * |
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378 | * @return object |
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379 | */ |
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380 | View Code Duplication | public function query($query, $con = NULL) |
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392 | } |
In PHP it is possible to write to properties without declaring them. For example, the following is perfectly valid PHP code:
Generally, it is a good practice to explictly declare properties to avoid accidental typos and provide IDE auto-completion: