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 Tables 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 Tables, and based on these observations, apply Extract Interface, too.
1 | <?php |
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37 | class Tables |
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38 | { |
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39 | /** |
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40 | * @var Connection |
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41 | */ |
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42 | protected $db; |
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43 | |||
44 | /** |
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45 | * @var string |
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46 | */ |
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47 | protected $databaseName; |
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48 | |||
49 | /** |
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50 | * @var array Tables |
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51 | */ |
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52 | protected $tables; |
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53 | |||
54 | /** |
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55 | * @var array Work queue |
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56 | */ |
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57 | protected $queue; |
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58 | |||
59 | /** |
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60 | * @var string last error message |
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61 | */ |
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62 | protected $lastError; |
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63 | |||
64 | /** |
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65 | * @var int last error number |
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66 | */ |
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67 | protected $lastErrNo; |
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68 | |||
69 | /** |
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70 | * Constructor |
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71 | * |
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72 | */ |
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73 | 1 | public function __construct() |
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81 | |||
82 | /** |
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83 | * Return a table name, prefixed with site table prefix |
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84 | * |
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85 | * @param string $table table name to contain prefix |
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86 | * |
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87 | * @return string table name with prefix |
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88 | */ |
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89 | 1 | protected function name($table) |
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93 | |||
94 | /** |
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95 | * Add new column for table to the work queue |
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96 | * |
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97 | * @param string $table table to contain the column |
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98 | * @param string $column name of column to add |
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99 | * @param string $attributes column_definition |
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100 | * |
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101 | * @return bool true if no errors, false if errors encountered |
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102 | */ |
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103 | 1 | public function addColumn($table, $column, $attributes) |
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132 | |||
133 | /** |
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134 | * Add new primary key definition for table to work queue |
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135 | * |
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136 | * @param string $table table |
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137 | * @param string $column column or comma separated list of columns |
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138 | * to use as primary key |
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139 | * |
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140 | * @return bool true if no errors, false if errors encountered |
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141 | */ |
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142 | 1 | public function addPrimaryKey($table, $column) |
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163 | |||
164 | /** |
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165 | * Add new index definition for index to work queue |
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166 | * |
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167 | * @param string $name name of index to add |
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168 | * @param string $table table indexed |
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169 | * @param string $column column or a comma separated list of columns |
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170 | * to use as the key |
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171 | * @param bool $unique true if index is to be unique |
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172 | * |
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173 | * @return bool true if no errors, false if errors encountered |
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174 | */ |
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175 | 1 | public function addIndex($name, $table, $column, $unique = false) |
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198 | |||
199 | /** |
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200 | * Load table schema from database, or starts new empty schema if |
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201 | * table does not exist |
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202 | * |
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203 | * @param string $table table |
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204 | * |
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205 | * @return bool true if no errors, false if errors encountered |
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206 | */ |
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207 | public function addTable($table) |
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236 | |||
237 | /** |
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238 | * AddTable only if it exists |
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239 | * |
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240 | * @param string $table table |
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241 | * |
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242 | * @return bool true if table exists, false otherwise |
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243 | */ |
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244 | 1 | public function useTable($table) |
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256 | |||
257 | /** |
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258 | * Get column attributes |
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259 | * |
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260 | * @param string $table table containing the column |
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261 | * @param string $column column to alter |
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262 | * |
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263 | * @return string|bool attribute string, or false if error encountered |
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264 | */ |
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265 | 1 | public function getColumnAttributes($table, $column) |
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280 | |||
281 | /** |
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282 | * Get indexes for a table |
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283 | * |
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284 | * @param string $table get indexes for this named table |
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285 | * |
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286 | * @return array|bool array of indexes, or false if error encountered |
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287 | */ |
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288 | 1 | public function getTableIndexes($table) |
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297 | |||
298 | /** |
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299 | * Add alter column operation to the work queue |
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300 | * |
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301 | * @param string $table table containing the column |
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302 | * @param string $column column to alter |
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303 | * @param string $attributes new column_definition |
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304 | * @param string $newName new name for column, blank to keep same |
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305 | * |
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306 | * @return bool true if no errors, false if errors encountered |
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307 | */ |
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308 | 1 | public function alterColumn($table, $column, $attributes, $newName = '') |
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346 | |||
347 | /** |
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348 | * Loads table schema from database, and adds newTable with that |
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349 | * schema to the queue |
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350 | * |
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351 | * @param string $table existing table |
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352 | * @param string $newTable new table |
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353 | * @param bool $withData true to copy data, false for schema only |
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354 | * |
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355 | * @return bool true if no errors, false if errors encountered |
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356 | */ |
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357 | 1 | public function copyTable($table, $newTable, $withData = false) |
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382 | |||
383 | /** |
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384 | * Add drop column operation to the work queue |
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385 | * |
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386 | * @param string $table table containing the column |
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387 | * @param string $column column to drop |
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388 | * |
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389 | * @return bool true if no errors, false if errors encountered |
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390 | */ |
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391 | 1 | View Code Duplication | public function dropColumn($table, $column) |
403 | |||
404 | /** |
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405 | * Add drop index operation to the work queue |
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406 | * |
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407 | * @param string $name name of index to drop |
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408 | * @param string $table table indexed |
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409 | * |
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410 | * @return bool true if no errors, false if errors encountered |
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411 | */ |
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412 | 1 | View Code Duplication | public function dropIndex($name, $table) |
423 | |||
424 | /** |
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425 | * Add drop for all (non-PRIMARY) keys for a table to the work |
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426 | * queue. This can be used to clean up indexes with automatic names. |
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427 | * |
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428 | * @param string $table table indexed |
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429 | * |
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430 | * @return bool true if no errors, false if errors encountered |
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431 | */ |
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432 | public function dropIndexes($table) |
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459 | |||
460 | /** |
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461 | * Add drop of PRIMARY key for a table to the work queue |
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462 | * |
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463 | * @param string $table table |
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464 | * |
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465 | * @return bool true if no errors, false if errors encountered |
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466 | */ |
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467 | 1 | View Code Duplication | public function dropPrimaryKey($table) |
478 | |||
479 | /** |
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480 | * Add drop of table to the work queue |
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481 | * |
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482 | * @param string $table table |
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483 | * |
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484 | * @return bool true if no errors, false if errors encountered |
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485 | */ |
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486 | 1 | View Code Duplication | public function dropTable($table) |
496 | |||
497 | |||
498 | /** |
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499 | * Add rename table operation to the work queue |
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500 | * |
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501 | * @param string $table table |
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502 | * @param string $newName new table name |
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503 | * |
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504 | * @return bool true if no errors, false if errors encountered |
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505 | */ |
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506 | 1 | public function renameTable($table, $newName) |
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521 | |||
522 | /** |
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523 | * Add alter table table_options (ENGINE, DEFAULT CHARSET, etc.) |
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524 | * to work queue |
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525 | * |
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526 | * @param string $table table |
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527 | * @param string $options table_options |
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528 | * |
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529 | * @return bool true if no errors, false if errors encountered |
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530 | */ |
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531 | 1 | public function setTableOptions($table, $options) |
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549 | |||
550 | |||
551 | /** |
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552 | * Clear the work queue |
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553 | * |
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554 | * @return void |
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555 | */ |
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556 | 2 | public function resetQueue() |
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561 | |||
562 | /** |
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563 | * Executes the work queue |
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564 | * |
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565 | * @param bool $force true to force updates even if this is a 'GET' request |
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566 | * |
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567 | * @return bool true if no errors, false if errors encountered |
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568 | */ |
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569 | public function executeQueue($force = false) |
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589 | |||
590 | |||
591 | /** |
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592 | * Create a DELETE statement and add it to the work queue |
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593 | * |
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594 | * @param string $table table |
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595 | * @param string|CriteriaElement $criteria string where clause or object criteria |
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596 | * |
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597 | * @return bool true if no errors, false if errors encountered |
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598 | */ |
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599 | public function delete($table, $criteria) |
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616 | |||
617 | /** |
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618 | * Create an INSERT SQL statement and add it to the work queue. |
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619 | * |
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620 | * @param string $table table |
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621 | * @param array $columns array of 'column'=>'value' entries |
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622 | * @param boolean $quoteValue true to quote values, false if caller handles quoting |
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623 | * |
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624 | * @return boolean true if no errors, false if errors encountered |
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625 | */ |
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626 | public function insert($table, $columns, $quoteValue = true) |
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648 | |||
649 | /** |
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650 | * Create an UPDATE SQL statement and add it to the work queue |
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651 | * |
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652 | * @param string $table table |
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653 | * @param array $columns array of 'column'=>'value' entries |
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654 | * @param string|CriteriaElement $criteria string where clause or object criteria |
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655 | * @param boolean $quoteValue true to quote values, false if caller handles quoting |
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656 | * |
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657 | * @return boolean true if no errors, false if errors encountered |
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658 | */ |
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659 | public function update($table, $columns, $criteria, $quoteValue = true) |
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685 | |||
686 | /** |
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687 | * Add statement to remove all rows from a table to the work queue |
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688 | * |
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689 | * @param string $table table |
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690 | * |
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691 | * @return bool true if no errors, false if errors encountered |
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692 | */ |
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693 | View Code Duplication | public function truncate($table) |
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704 | |||
705 | |||
706 | |||
707 | /** |
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708 | * return SQL to create the table |
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709 | * |
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710 | * This method does NOT modify the work queue |
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711 | * |
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712 | * @param string $table table |
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713 | * @param bool $prefixed true to return with table name prefixed |
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714 | * |
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715 | * @return string|false string SQL to create table, or false if errors encountered |
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716 | */ |
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717 | protected function renderTableCreate($table, $prefixed = false) |
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745 | |||
746 | /** |
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747 | * execute an SQL statement |
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748 | * |
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749 | * @param string $sql SQL statement to execute |
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750 | * @param bool $force true to use force updates even in safe requests |
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751 | * |
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752 | * @return mixed result Statement, or false on error |
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753 | * Any error message is in $this->lastError; |
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754 | */ |
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755 | protected function execSql($sql, $force = false) |
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769 | |||
770 | /** |
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771 | * fetch the next row of a result set |
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772 | * |
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773 | * @param Statement $result as returned by query |
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774 | * |
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775 | * @return mixed false on error |
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776 | */ |
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777 | protected function fetch($result) |
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781 | |||
782 | /** |
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783 | * get table definition from INFORMATION_SCHEMA |
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784 | * |
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785 | * @param string $table table |
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786 | * |
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787 | * @return array|bool table definition array if table exists, true if table not defined, or |
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788 | * false on error. Error message in $this->lastError; |
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789 | */ |
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790 | protected function getTable($table) |
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873 | |||
874 | /** |
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875 | * During processing, tables to be created are put in the queue as |
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876 | * an array('createtable' => tablename) since the definition is not |
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877 | * complete. This method will expand those references to the full |
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878 | * ddl to create the table. |
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879 | * |
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880 | * @return void |
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881 | */ |
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882 | protected function expandQueue() |
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892 | |||
893 | /** |
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894 | * Return message from last error encountered |
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895 | * |
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896 | * @return string last error message |
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897 | */ |
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898 | public function getLastError() |
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902 | |||
903 | /** |
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904 | * Return code from last error encountered |
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905 | * |
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906 | * @return int last error number |
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907 | */ |
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908 | public function getLastErrNo() |
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912 | |||
913 | /** |
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914 | * dumpTables - utility function to dump raw tables array |
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915 | * |
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916 | * @return array tables |
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917 | */ |
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918 | public function dumpTables() |
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922 | |||
923 | /** |
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924 | * dumpQueue - utility function to dump the work queue |
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925 | * |
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926 | * @return array work queue |
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927 | */ |
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928 | 1 | public function dumpQueue() |
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934 | |||
935 | /** |
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936 | * addToQueue - utility function to add a statement to the work queue |
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937 | * |
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938 | * @param string $sql an SQL/DDL statement to add |
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939 | * |
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940 | * @return void |
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941 | */ |
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942 | 1 | public function addToQueue($sql) |
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946 | |||
947 | /** |
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948 | * Set lastError as table not established |
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949 | * |
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950 | * @return false |
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951 | */ |
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952 | protected function tableNotEstablished() |
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958 | } |
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959 |