phpmyadmin /
error-reporting-server
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:
| 1 | <?php |
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| 22 | trait SqlDialectTrait |
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| 23 | { |
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| 24 | |||
| 25 | /** |
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| 26 | * Quotes a database identifier (a column name, table name, etc..) to |
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| 27 | * be used safely in queries without the risk of using reserved words |
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| 28 | * |
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| 29 | * @param string $identifier The identifier to quote. |
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| 30 | * @return string |
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| 31 | */ |
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| 32 | public function quoteIdentifier($identifier) |
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| 33 | { |
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| 34 | $identifier = trim($identifier); |
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| 35 | |||
| 36 | if ($identifier === '*') { |
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| 37 | return '*'; |
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| 38 | } |
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| 39 | |||
| 40 | if ($identifier === '') { |
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| 41 | return ''; |
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| 42 | } |
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| 43 | |||
| 44 | // string |
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| 45 | if (preg_match('/^[\w-]+$/', $identifier)) { |
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| 46 | return $this->_startQuote . $identifier . $this->_endQuote; |
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| 47 | } |
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| 48 | |||
| 49 | if (preg_match('/^[\w-]+\.[^ \*]*$/', $identifier)) { |
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| 50 | // string.string |
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| 51 | $items = explode('.', $identifier); |
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| 52 | return $this->_startQuote . implode($this->_endQuote . '.' . $this->_startQuote, $items) . $this->_endQuote; |
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| 53 | } |
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| 54 | |||
| 55 | if (preg_match('/^[\w-]+\.\*$/', $identifier)) { |
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| 56 | // string.* |
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| 57 | return $this->_startQuote . str_replace('.*', $this->_endQuote . '.*', $identifier); |
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| 58 | } |
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| 59 | |||
| 60 | View Code Duplication | if (preg_match('/^([\w-]+)\((.*)\)$/', $identifier, $matches)) { |
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| 61 | // Functions |
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| 62 | return $matches[1] . '(' . $this->quoteIdentifier($matches[2]) . ')'; |
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| 63 | } |
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| 64 | |||
| 65 | // Alias.field AS thing |
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| 66 | View Code Duplication | if (preg_match('/^([\w-]+(\.[\w-]+|\(.*\))*)\s+AS\s*([\w-]+)$/i', $identifier, $matches)) { |
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| 67 | return $this->quoteIdentifier($matches[1]) . ' AS ' . $this->quoteIdentifier($matches[3]); |
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| 68 | } |
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| 69 | |||
| 70 | if (preg_match('/^[\w-_\s]*[\w-_]+/', $identifier)) { |
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| 71 | return $this->_startQuote . $identifier . $this->_endQuote; |
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| 72 | } |
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| 73 | |||
| 74 | return $identifier; |
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| 75 | } |
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| 76 | |||
| 77 | /** |
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| 78 | * Returns a callable function that will be used to transform a passed Query object. |
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| 79 | * This function, in turn, will return an instance of a Query object that has been |
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| 80 | * transformed to accommodate any specificities of the SQL dialect in use. |
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| 81 | * |
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| 82 | * @param string $type the type of query to be transformed |
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| 83 | * (select, insert, update, delete) |
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| 84 | * @return callable |
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| 85 | */ |
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| 86 | public function queryTranslator($type) |
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| 87 | { |
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| 88 | return function ($query) use ($type) { |
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| 89 | if ($this->autoQuoting()) { |
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| 90 | $query = (new IdentifierQuoter($this))->quote($query); |
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| 91 | } |
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| 92 | |||
| 93 | $query = $this->{'_' . $type . 'QueryTranslator'}($query); |
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| 94 | $translators = $this->_expressionTranslators(); |
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| 95 | if (!$translators) { |
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| 96 | return $query; |
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| 97 | } |
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| 98 | |||
| 99 | $query->traverseExpressions(function ($expression) use ($translators, $query) { |
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| 100 | foreach ($translators as $class => $method) { |
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| 101 | if ($expression instanceof $class) { |
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| 102 | $this->{$method}($expression, $query); |
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| 103 | } |
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| 104 | } |
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| 105 | }); |
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| 106 | return $query; |
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| 107 | }; |
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| 108 | } |
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| 109 | |||
| 110 | /** |
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| 111 | * Returns an associative array of methods that will transform Expression |
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| 112 | * objects to conform with the specific SQL dialect. Keys are class names |
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| 113 | * and values a method in this class. |
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| 114 | * |
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| 115 | * @return array |
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| 116 | */ |
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| 117 | protected function _expressionTranslators() |
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| 121 | |||
| 122 | /** |
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| 123 | * Apply translation steps to select queries. |
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| 124 | * |
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| 125 | * @param \Cake\Database\Query $query The query to translate |
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| 126 | * @return \Cake\Database\Query The modified query |
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| 127 | */ |
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| 128 | protected function _selectQueryTranslator($query) |
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| 132 | |||
| 133 | /** |
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| 134 | * Returns the passed query after rewriting the DISTINCT clause, so that drivers |
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| 135 | * that do not support the "ON" part can provide the actual way it should be done |
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| 136 | * |
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| 137 | * @param \Cake\Database\Query $query The query to be transformed |
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| 138 | * @return \Cake\Database\Query |
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| 139 | */ |
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| 140 | protected function _transformDistinct($query) |
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| 148 | |||
| 149 | /** |
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| 150 | * Apply translation steps to delete queries. |
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| 151 | * |
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| 152 | * Chops out aliases on delete query conditions as most database dialects do not |
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| 153 | * support aliases in delete queries. This also removes aliases |
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| 154 | * in table names as they frequently don't work either. |
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| 155 | * |
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| 156 | * We are intentionally not supporting deletes with joins as they have even poorer support. |
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| 157 | * |
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| 158 | * @param \Cake\Database\Query $query The query to translate |
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| 159 | * @return \Cake\Database\Query The modified query |
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| 160 | */ |
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| 161 | protected function _deleteQueryTranslator($query) |
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| 198 | |||
| 199 | /** |
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| 200 | * Apply translation steps to update queries. |
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| 201 | * |
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| 202 | * @param \Cake\Database\Query $query The query to translate |
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| 203 | * @return \Cake\Database\Query The modified query |
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| 204 | */ |
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| 205 | protected function _updateQueryTranslator($query) |
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| 209 | |||
| 210 | /** |
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| 211 | * Apply translation steps to insert queries. |
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| 212 | * |
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| 213 | * @param \Cake\Database\Query $query The query to translate |
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| 214 | * @return \Cake\Database\Query The modified query |
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| 215 | */ |
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| 216 | protected function _insertQueryTranslator($query) |
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| 220 | |||
| 221 | /** |
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| 222 | * Returns a SQL snippet for creating a new transaction savepoint |
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| 223 | * |
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| 224 | * @param string $name save point name |
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| 225 | * @return string |
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| 226 | */ |
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| 227 | public function savePointSQL($name) |
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| 231 | |||
| 232 | /** |
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| 233 | * Returns a SQL snippet for releasing a previously created save point |
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| 234 | * |
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| 235 | * @param string $name save point name |
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| 236 | * @return string |
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| 237 | */ |
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| 238 | public function releaseSavePointSQL($name) |
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| 242 | |||
| 243 | /** |
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| 244 | * Returns a SQL snippet for rollbacking a previously created save point |
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| 245 | * |
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| 246 | * @param string $name save point name |
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| 247 | * @return string |
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| 248 | */ |
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| 249 | public function rollbackSavePointSQL($name) |
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| 253 | } |
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| 254 |
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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: