| Total Complexity | 50 | 
| Total Lines | 291 | 
| Duplicated Lines | 0 % | 
| Changes | 1 | ||
| Bugs | 0 | Features | 0 | 
Complex classes like NullDatabase 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.
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 NullDatabase, and based on these observations, apply Extract Interface, too.
| 1 | <?php  | 
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| 22 | class NullDatabase extends Database  | 
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| 23 | { | 
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| 24 | |||
| 25 | /**  | 
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| 26 | * @var string  | 
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| 27 | */  | 
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| 28 | protected $errorMessage = 'Using NullDatabase, cannot interact with database';  | 
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| 29 | |||
| 30 | /**  | 
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| 31 | * @var string  | 
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| 32 | */  | 
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| 33 | protected $queryErrorMessage = 'Using NullDatabase, cannot execute query: %s';  | 
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| 34 | |||
| 35 | /**  | 
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| 36 | * @param string $msg  | 
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| 37 | * @return self  | 
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| 38 | */  | 
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| 39 | public function setErrorMessage(string $msg)  | 
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| 40 |     { | 
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| 41 | $this->errorMessage = $msg;  | 
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| 42 | return $this;  | 
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| 43 | }  | 
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| 44 | |||
| 45 | /**  | 
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| 46 | * @param string $msg  | 
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| 47 | * @return self  | 
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| 48 | */  | 
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| 49 | public function setQueryErrorMessage(string $msg)  | 
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| 50 |     { | 
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| 51 | $this->queryErrorMessage = $msg;  | 
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| 52 | return $this;  | 
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| 53 | }  | 
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| 54 | |||
| 55 | public function query($sql, $errorLevel = E_USER_ERROR)  | 
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| 56 |     { | 
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| 57 | throw new NullDatabaseException(sprintf($this->queryErrorMessage, $sql));  | 
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| 58 | }  | 
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| 59 | |||
| 60 | public function preparedQuery($sql, $parameters, $errorLevel = E_USER_ERROR)  | 
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| 61 |     { | 
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| 62 | throw new NullDatabaseException(sprintf($this->queryErrorMessage, $sql));  | 
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| 63 | }  | 
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| 64 | |||
| 65 | public function getConnector()  | 
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| 66 |     { | 
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| 67 | throw new NullDatabaseException($this->errorMessage);  | 
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| 68 | }  | 
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| 69 | |||
| 70 | public function getSchemaManager()  | 
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| 71 |     { | 
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| 72 | throw new NullDatabaseException($this->errorMessage);  | 
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| 73 | }  | 
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| 74 | |||
| 75 | public function getQueryBuilder()  | 
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| 76 |     { | 
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| 77 | throw new NullDatabaseException($this->errorMessage);  | 
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| 78 | }  | 
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| 79 | |||
| 80 | public function getGeneratedID($table)  | 
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| 81 |     { | 
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| 82 | // no-op  | 
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| 83 | }  | 
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| 84 | |||
| 85 | public function isActive()  | 
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| 86 |     { | 
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| 87 | return true;  | 
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| 88 | }  | 
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| 89 | |||
| 90 | public function escapeString($value)  | 
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| 91 |     { | 
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| 92 | return $value;  | 
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| 93 | }  | 
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| 94 | |||
| 95 | public function quoteString($value)  | 
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| 96 |     { | 
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| 97 | return $value;  | 
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| 98 | }  | 
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| 99 | |||
| 100 | public function escapeIdentifier($value, $separator = '.')  | 
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| 101 |     { | 
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| 102 | return $value;  | 
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| 103 | }  | 
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| 104 | |||
| 105 | protected function escapeColumnKeys($fieldValues)  | 
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| 106 |     { | 
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| 107 | return $fieldValues;  | 
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| 108 | }  | 
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| 109 | |||
| 110 | public function manipulate($manipulation)  | 
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| 111 |     { | 
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| 112 | throw new NullDatabaseException($this->errorMessage);  | 
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| 113 | }  | 
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| 114 | |||
| 115 | public function clearAllData()  | 
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| 116 |     { | 
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| 117 | throw new NullDatabaseException($this->errorMessage);  | 
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| 118 | }  | 
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| 119 | |||
| 120 | public function clearTable($table)  | 
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| 121 |     { | 
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| 122 | throw new NullDatabaseException($this->errorMessage);  | 
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| 123 | }  | 
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| 124 | |||
| 125 | public function nullCheckClause($field, $isNull)  | 
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| 126 |     { | 
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| 127 | return '';  | 
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| 128 | }  | 
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| 129 | |||
| 130 | public function comparisonClause(  | 
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| 131 | $field,  | 
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| 132 | $value,  | 
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| 133 | $exact = false,  | 
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| 134 | $negate = false,  | 
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| 135 | $caseSensitive = null,  | 
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| 136 | $parameterised = false  | 
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| 137 |     ) { | 
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| 138 | return '';  | 
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| 139 | }  | 
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| 140 | |||
| 141 | public function formattedDatetimeClause($date, $format)  | 
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| 142 |     { | 
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| 143 | return '';  | 
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| 144 | }  | 
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| 145 | |||
| 146 | public function datetimeIntervalClause($date, $interval)  | 
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| 147 |     { | 
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| 148 | return '';  | 
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| 149 | }  | 
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| 150 | |||
| 151 | public function datetimeDifferenceClause($date1, $date2)  | 
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| 152 |     { | 
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| 153 | return '';  | 
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| 154 | }  | 
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| 155 | |||
| 156 | public function concatOperator()  | 
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| 157 |     { | 
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| 158 | return '';  | 
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| 159 | }  | 
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| 160 | |||
| 161 | public function supportsCollations()  | 
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| 162 |     { | 
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| 163 | return false;  | 
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| 164 | }  | 
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| 165 | |||
| 166 | public function supportsTimezoneOverride()  | 
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| 167 |     { | 
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| 168 | return false;  | 
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| 169 | }  | 
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| 170 | |||
| 171 | public function getVersion()  | 
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| 172 |     { | 
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| 173 | return '';  | 
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| 174 | }  | 
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| 175 | |||
| 176 | public function getDatabaseServer()  | 
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| 177 |     { | 
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| 178 | return '';  | 
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| 179 | }  | 
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| 180 | |||
| 181 | public function affectedRows()  | 
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| 182 |     { | 
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| 183 | return 0;  | 
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| 184 | }  | 
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| 185 | |||
| 186 | public function searchEngine(  | 
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| 187 | $classesToSearch,  | 
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| 188 | $keywords,  | 
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| 189 | $start,  | 
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| 190 | $pageLength,  | 
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| 191 | $sortBy = "Relevance DESC",  | 
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| 192 | $extraFilter = "",  | 
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| 193 | $booleanSearch = false,  | 
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| 194 | $alternativeFileFilter = "",  | 
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| 195 | $invertedMatch = false  | 
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| 196 |     ) { | 
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| 197 | // no-op  | 
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| 198 | }  | 
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| 199 | |||
| 200 | public function supportsTransactions()  | 
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| 201 |     { | 
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| 202 | return false;  | 
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| 203 | }  | 
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| 204 | |||
| 205 | public function supportsSavepoints()  | 
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| 206 |     { | 
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| 207 | return false;  | 
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| 208 | }  | 
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| 209 | |||
| 210 | |||
| 211 | public function supportsTransactionMode(string $mode): bool  | 
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| 212 |     { | 
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| 213 | return false;  | 
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| 214 | }  | 
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| 215 | |||
| 216 | public function withTransaction(  | 
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| 217 | $callback,  | 
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| 218 | $errorCallback = null,  | 
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| 219 | $transactionMode = false,  | 
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| 220 | $errorIfTransactionsUnsupported = false  | 
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| 221 |     ) { | 
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| 222 | // no-op  | 
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| 223 | }  | 
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| 224 | |||
| 225 | public function supportsExtensions($extensions)  | 
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| 226 |     { | 
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| 227 | return false;  | 
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| 228 | }  | 
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| 229 | |||
| 230 | public function transactionStart($transactionMode = false, $sessionCharacteristics = false)  | 
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| 231 |     { | 
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| 232 | // no-op  | 
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| 233 | }  | 
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| 234 | |||
| 235 | public function transactionSavepoint($savepoint)  | 
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| 236 |     { | 
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| 237 | // no-op  | 
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| 238 | }  | 
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| 239 | |||
| 240 | public function transactionRollback($savepoint = false)  | 
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| 241 |     { | 
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| 242 | // no-op  | 
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| 243 | }  | 
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| 244 | |||
| 245 | public function transactionEnd($chain = false)  | 
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| 247 | // no-op  | 
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| 248 | }  | 
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| 249 | |||
| 250 | public function transactionDepth()  | 
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| 251 |     { | 
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| 252 | return 0;  | 
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| 253 | }  | 
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| 254 | |||
| 255 | public function supportsLocks()  | 
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| 256 |     { | 
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| 257 | return false;  | 
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| 258 | }  | 
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| 259 | |||
| 260 | public function canLock($name)  | 
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| 261 |     { | 
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| 262 | return false;  | 
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| 263 | }  | 
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| 264 | |||
| 265 | public function getLock($name, $timeout = 5)  | 
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| 266 |     { | 
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| 267 | return false;  | 
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| 268 | }  | 
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| 269 | |||
| 270 | public function releaseLock($name)  | 
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| 271 |     { | 
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| 272 | return false;  | 
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| 273 | }  | 
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| 274 | |||
| 275 | public function connect($parameters)  | 
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| 276 |     { | 
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| 277 | // no-op  | 
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| 278 | }  | 
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| 279 | |||
| 280 | public function databaseExists($name)  | 
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| 281 |     { | 
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| 282 | return false;  | 
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| 283 | }  | 
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| 284 | |||
| 285 | public function databaseList()  | 
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| 286 |     { | 
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| 287 | return [];  | 
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| 288 | }  | 
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| 289 | |||
| 290 | public function selectDatabase($name, $create = false, $errorLevel = E_USER_ERROR)  | 
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| 292 | // no-op  | 
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| 293 | }  | 
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| 294 | |||
| 295 | public function dropSelectedDatabase()  | 
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| 296 |     { | 
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| 297 | // no-op  | 
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| 298 | }  | 
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| 299 | |||
| 300 | public function getSelectedDatabase()  | 
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| 301 |     { | 
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| 302 | // no-op  | 
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| 303 | }  | 
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| 304 | |||
| 305 | public function now()  | 
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| 306 |     { | 
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| 307 | return '';  | 
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| 308 | }  | 
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| 309 | |||
| 310 | public function random()  | 
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| 313 | }  | 
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| 314 | }  | 
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| 315 |