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 Give_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 Give_DB, and based on these observations, apply Extract Interface, too.
1 | <?php |
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24 | abstract class Give_DB { |
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25 | |||
26 | /** |
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27 | * The name of our database table |
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28 | * |
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29 | * @since 1.0 |
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30 | * @access public |
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31 | * |
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32 | * @var string |
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33 | */ |
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34 | public $table_name; |
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35 | |||
36 | /** |
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37 | * Set Minimum Index Length |
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38 | * |
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39 | * @since 2.0.1 |
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40 | * @access public |
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41 | * |
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42 | * @var int |
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43 | */ |
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44 | public $min_index_length = 191; |
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45 | |||
46 | /** |
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47 | * The version of our database table |
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48 | * |
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49 | * @since 1.0 |
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50 | * @access public |
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51 | * |
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52 | * @var string |
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53 | */ |
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54 | public $version; |
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55 | |||
56 | /** |
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57 | * The name of the primary column |
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58 | * |
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59 | * @since 1.0 |
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60 | * @access public |
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61 | * |
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62 | * @var string |
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63 | */ |
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64 | public $primary_key; |
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65 | |||
66 | /** |
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67 | * Class Constructor |
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68 | * |
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69 | * Set up the Give DB Class. |
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70 | * |
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71 | * @since 1.0 |
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72 | * @access public |
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73 | */ |
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74 | public function __construct() { |
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79 | |||
80 | /** |
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81 | * Whitelist of columns |
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82 | * |
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83 | * @since 1.0 |
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84 | * @access public |
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85 | * |
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86 | * @return array Columns and formats. |
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87 | */ |
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88 | public function get_columns() { |
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91 | |||
92 | /** |
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93 | * Default column values |
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94 | * |
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95 | * @since 1.0 |
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96 | * @access public |
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97 | * |
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98 | * @return array Default column values. |
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99 | */ |
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100 | public function get_column_defaults() { |
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103 | |||
104 | /** |
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105 | * Retrieve a row by the primary key |
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106 | * |
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107 | * @since 1.0 |
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108 | * @access public |
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109 | 52 | * |
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110 | 52 | * @param int $row_id Row ID. |
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111 | 52 | * |
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112 | 52 | * @return object |
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113 | */ |
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114 | public function get( $row_id ) { |
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125 | 2 | ||
126 | 2 | /** |
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127 | * Retrieve a row by a specific column / value |
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128 | * |
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129 | * @since 1.0 |
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130 | * @access public |
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131 | * |
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132 | * @param int $column Column ID. |
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133 | * @param int $row_id Row ID. |
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134 | * |
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135 | * @return object |
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136 | 52 | */ |
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137 | 52 | View Code Duplication | public function get_by( $column, $row_id ) { |
150 | |||
151 | 52 | /** |
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152 | * Retrieve all rows by a specific column / value |
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153 | * Note: currently support string comparision |
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154 | 52 | * |
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155 | 52 | * @since 2.2.4 |
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156 | * @access public |
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157 | 52 | * |
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158 | * @param array $column_args Array contains column key and expected value. |
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159 | 52 | * |
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160 | * @return array |
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161 | 52 | */ |
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162 | public function get_results_by( $column_args ) { |
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189 | |||
190 | 52 | /** |
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191 | * Retrieve a specific column's value by the primary key |
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192 | * |
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193 | 52 | * @since 1.0 |
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194 | * @access public |
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195 | * |
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196 | 52 | * @param int $column Column ID. |
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197 | 52 | * @param int $row_id Row ID. |
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198 | * |
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199 | 52 | * @return string Column value. |
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200 | */ |
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201 | View Code Duplication | public function get_column( $column, $row_id ) { |
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214 | |||
215 | /** |
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216 | * Retrieve a specific column's value by the the specified column / value |
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217 | * |
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218 | * @since 1.0 |
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219 | * @access public |
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220 | * |
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221 | * @param int $column Column ID. |
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222 | * @param string $column_where Column name. |
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223 | * @param string $column_value Column value. |
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224 | * |
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225 | * @return string |
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226 | */ |
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227 | public function get_column_by( $column, $column_where, $column_value ) { |
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241 | |||
242 | 2 | /** |
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243 | * Insert a new row |
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244 | * |
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245 | * @since 1.0 |
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246 | * @access public |
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247 | * |
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248 | * @param array $data |
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249 | * @param string $type |
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250 | * |
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251 | * @return int |
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252 | */ |
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253 | public function insert( $data, $type = '' ) { |
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296 | |||
297 | /** |
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298 | * Update a row |
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299 | * |
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300 | * @since 1.0 |
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301 | * @access public |
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302 | * |
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303 | * @param int $row_id Column ID |
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304 | * @param array $data |
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305 | * @param string $where Column value |
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306 | * |
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307 | * @return bool |
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308 | */ |
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309 | public function update( $row_id, $data = array(), $where = '' ) { |
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343 | |||
344 | /** |
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345 | * Delete a row identified by the primary key |
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346 | * |
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347 | * @since 1.0 |
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348 | * @access public |
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349 | * |
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350 | * @param int $row_id Column ID. |
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351 | * |
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352 | * @return bool |
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353 | */ |
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354 | View Code Duplication | public function delete( $row_id = 0 ) { |
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371 | |||
372 | /** |
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373 | * Check if the given table exists |
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374 | * |
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375 | * @since 1.3.2 |
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376 | * @access public |
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377 | * |
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378 | * @param string $table The table name. |
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379 | * |
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380 | * @return bool If the table name exists. |
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381 | */ |
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382 | public function table_exists( $table ) { |
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390 | |||
391 | /** |
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392 | * Checks whether column exists in a table or not. |
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393 | * |
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394 | * @param string $column_name Name of the Column in Database Table. |
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395 | * |
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396 | * @since 1.8.18 |
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397 | * |
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398 | * @see https://gist.github.com/datafeedr/54e89e07f87232fb055121bb766743fe |
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399 | * |
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400 | * @return bool |
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401 | */ |
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402 | public function does_column_exist( $column_name ) { |
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417 | |||
418 | /** |
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419 | * Check if the table was ever installed |
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420 | * |
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421 | * @since 1.6 |
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422 | * @access public |
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423 | * |
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424 | * @return bool Returns if the customers table was installed and upgrade routine run. |
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425 | */ |
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426 | public function installed() { |
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429 | |||
430 | /** |
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431 | * Register tables |
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432 | * |
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433 | * @since 1.8.9 |
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434 | * @access public |
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435 | */ |
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436 | public function register_table() { |
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442 | |||
443 | /** |
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444 | * Create table |
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445 | * |
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446 | * @since 1.8.9 |
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447 | * @access public |
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448 | */ |
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449 | public function create_table() { |
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451 | |||
452 | |||
453 | /** |
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454 | * Given a ID, make sure it's a positive number, greater than zero before inserting or adding. |
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455 | * |
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456 | * @access private |
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457 | * @since 2.0 |
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458 | * |
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459 | * @param int $id A passed ID. |
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460 | * |
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461 | * @return int|bool The normalized log ID or false if it's found to not be valid. |
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462 | */ |
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463 | public function sanitize_id( $id ) { |
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482 | |||
483 | /** |
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484 | * Handle switch blog on multi-site |
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485 | * |
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486 | * @since 2.0.4 |
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487 | * |
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488 | * @access public |
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489 | * |
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490 | * @param $new_blog_id |
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491 | * @param $prev_blog_id |
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492 | */ |
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493 | public function handle_switch_blog( $new_blog_id, $prev_blog_id ) { |
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513 | } |
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514 |