Complex classes like Connection 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 Connection, and based on these observations, apply Extract Interface, too.
| 1 | <?php |
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| 25 | class Connection |
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| 26 | { |
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| 27 | const CONNECTION_STATUS_NONE = 0; |
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| 28 | const CONNECTION_STATUS_GOOD = 1; |
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| 29 | const CONNECTION_STATUS_BAD = 2; |
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| 30 | const CONNECTION_STATUS_CLOSED = 3; |
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| 31 | const ISOLATION_READ_COMMITTED = "READ COMMITTED"; // default |
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| 32 | const ISOLATION_REPEATABLE_READ = "REPEATABLE READ"; // from Pg 9.1 |
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| 33 | const ISOLATION_SERIALIZABLE = "SERIALIZABLE"; // changes in 9.1 |
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| 34 | const CONSTRAINTS_DEFERRED = "DEFERRED"; |
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| 35 | const CONSTRAINTS_IMMEDIATE = "IMMEDIATE"; // default |
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| 36 | const ACCESS_MODE_READ_ONLY = "READ ONLY"; |
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| 37 | const ACCESS_MODE_READ_WRITE = "READ WRITE"; // default |
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| 38 | |||
| 39 | protected $handler; |
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| 40 | protected $configurator; |
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| 41 | private $is_closed = false; |
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| 42 | |||
| 43 | /** |
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| 44 | * __construct |
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| 45 | * |
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| 46 | * Constructor. Test if the given DSN is valid. |
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| 47 | * |
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| 48 | * @access public |
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| 49 | * @param string $dsn |
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| 50 | * @param array $configuration |
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| 51 | * @throws ConnectionException if pgsql extension is missing |
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| 52 | */ |
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| 53 | public function __construct($dsn, array $configuration = []) |
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| 54 | { |
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| 55 | if (!function_exists('pg_connection_status')) { |
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| 56 | throw new ConnectionException("`pgsql` PHP extension's functions are unavailable in your environment, please make sure PostgreSQL support is enabled in PHP."); |
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| 57 | } |
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| 58 | |||
| 59 | $this->configurator = new ConnectionConfigurator($dsn); |
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| 60 | $this->configurator->addConfiguration($configuration); |
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| 61 | } |
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| 62 | |||
| 63 | /** |
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| 64 | * close |
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| 65 | * |
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| 66 | * Close the connection if any. |
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| 67 | * |
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| 68 | * @access public |
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| 69 | * @return Connection $this |
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| 70 | */ |
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| 71 | public function close() |
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| 72 | { |
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| 73 | if ($this->hasHandler()) { |
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| 74 | pg_close($this->handler); |
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| 75 | $this->handler = null; |
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| 76 | $this->is_closed = true; |
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| 77 | } |
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| 78 | |||
| 79 | return $this; |
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| 80 | } |
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| 81 | |||
| 82 | /** |
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| 83 | * addConfiguration |
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| 84 | * |
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| 85 | * Add configuration settings. If settings exist, they are overridden. |
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| 86 | * |
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| 87 | * @access public |
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| 88 | * @param array $configuration |
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| 89 | * @throws ConnectionException if connection is already up. |
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| 90 | * @return Connection $this |
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| 91 | */ |
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| 92 | public function addConfiguration(array $configuration) |
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| 93 | { |
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| 94 | $this |
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| 95 | ->checkConnectionUp("Cannot update configuration once the connection is open.") |
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| 96 | ->configurator->addConfiguration($configuration); |
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| 97 | |||
| 98 | return $this; |
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| 99 | } |
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| 100 | |||
| 101 | /** |
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| 102 | * addConfigurationSetting |
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| 103 | * |
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| 104 | * Add or override a configuration definition. |
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| 105 | * |
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| 106 | * @access public |
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| 107 | * @param string $name |
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| 108 | * @param string $value |
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| 109 | * @return Connection |
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| 110 | */ |
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| 111 | public function addConfigurationSetting($name, $value) |
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| 112 | { |
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| 113 | $this->checkConnectionUp("Cannot set configuration once a connection is made with the server.") |
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| 114 | ->configurator->set($name, $value); |
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| 115 | |||
| 116 | return $this; |
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| 117 | } |
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| 118 | |||
| 119 | /** |
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| 120 | * getHandler |
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| 121 | * |
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| 122 | * Return the connection handler. If no connection are open, it opens one. |
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| 123 | * |
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| 124 | * @access protected |
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| 125 | * @throws ConnectionException if connection is open in a bad state. |
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| 126 | * @return resource |
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| 127 | */ |
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| 128 | protected function getHandler() |
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| 129 | { |
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| 130 | switch ($this->getConnectionStatus()) { |
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| 131 | case static::CONNECTION_STATUS_NONE: |
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| 132 | $this->launch(); |
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| 133 | // no break |
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| 134 | case static::CONNECTION_STATUS_GOOD: |
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| 135 | return $this->handler; |
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| 136 | case static::CONNECTION_STATUS_BAD: |
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| 137 | throw new ConnectionException( |
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| 138 | "Connection problem. Read your server's log about this, I have no more informations." |
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| 139 | ); |
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| 140 | case static::CONNECTION_STATUS_CLOSED: |
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| 141 | throw new ConnectionException( |
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| 142 | "Connection has been closed, no further queries can be sent." |
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| 143 | ); |
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| 144 | } |
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| 145 | } |
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| 146 | |||
| 147 | /** |
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| 148 | * hasHandler |
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| 149 | * |
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| 150 | * Tell if a handler is set or not. |
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| 151 | * |
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| 152 | * @access protected |
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| 153 | * @return bool |
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| 154 | */ |
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| 155 | protected function hasHandler() |
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| 156 | { |
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| 157 | return (bool) ($this->handler !== null); |
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| 158 | } |
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| 159 | |||
| 160 | /** |
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| 161 | * getConnectionStatus |
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| 162 | * |
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| 163 | * Return a connection status. |
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| 164 | * |
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| 165 | * @access public |
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| 166 | * @return int |
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| 167 | */ |
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| 168 | public function getConnectionStatus() |
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| 184 | |||
| 185 | /** |
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| 186 | * getTransactionStatus |
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| 187 | * |
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| 188 | * Return the current transaction status. |
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| 189 | * Return a PHP constant. |
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| 190 | * @see http://fr2.php.net/manual/en/function.pg-transaction-status.php |
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| 191 | * |
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| 192 | * @access public |
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| 193 | * @return int |
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| 194 | */ |
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| 195 | public function getTransactionStatus() |
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| 196 | { |
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| 197 | return pg_transaction_status($this->handler); |
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| 198 | } |
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| 199 | |||
| 200 | /** |
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| 201 | * launch |
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| 202 | * |
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| 203 | * Open a connection on the database. |
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| 204 | * |
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| 205 | * @access private |
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| 206 | * @throws ConnectionException if connection fails. |
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| 207 | * return Connection $this |
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| 208 | */ |
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| 209 | private function launch() |
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| 210 | { |
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| 211 | $string = $this->configurator->getConnectionString(); |
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| 212 | $handler = pg_connect($string, \PGSQL_CONNECT_FORCE_NEW); |
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| 213 | |||
| 214 | if ($handler === false) { |
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| 215 | throw new ConnectionException( |
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| 216 | sprintf( |
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| 217 | "Error connecting to the database with parameters '%s'.", |
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| 218 | preg_replace('/password=[^ ]+/', 'password=xxxx', $string) |
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| 219 | ) |
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| 220 | ); |
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| 221 | } else { |
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| 222 | $this->handler = $handler; |
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| 223 | } |
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| 224 | |||
| 225 | if ($this->getConnectionStatus() !== static::CONNECTION_STATUS_GOOD) { |
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| 226 | throw new ConnectionException( |
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| 227 | "Connection open but in a bad state. Read your database server log to learn more about this." |
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| 228 | ); |
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| 229 | } |
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| 230 | |||
| 231 | $this->sendConfiguration(); |
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| 232 | |||
| 233 | return $this; |
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| 234 | } |
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| 235 | |||
| 236 | /** |
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| 237 | * sendConfiguration |
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| 238 | * |
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| 239 | * Send the configuration settings to the server. |
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| 240 | * |
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| 241 | * @access protected |
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| 242 | * @return Connection $this |
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| 243 | */ |
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| 244 | protected function sendConfiguration() |
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| 245 | { |
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| 246 | $sql=[]; |
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| 247 | |||
| 248 | foreach ($this->configurator->getConfiguration() as $setting => $value) { |
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| 249 | $sql[] = sprintf("set %s = %s", pg_escape_identifier($this->handler, $setting), pg_escape_literal($this->handler, $value)); |
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| 250 | } |
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| 251 | |||
| 252 | if (count($sql) > 0) { |
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| 253 | $this->testQuery( |
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| 254 | pg_query($this->getHandler(), join('; ', $sql)), |
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| 255 | sprintf("Error while applying settings '%s'.", join('; ', $sql)) |
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| 256 | ); |
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| 257 | } |
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| 258 | |||
| 259 | return $this; |
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| 260 | } |
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| 261 | |||
| 262 | /** |
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| 263 | * checkConnectionUp |
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| 264 | * |
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| 265 | * Check if the handler is set and throw an Exception if yes. |
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| 266 | * |
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| 267 | * @access private |
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| 268 | * @param string $error_message |
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| 269 | * @throws ConnectionException |
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| 270 | * @return Connection $this |
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| 271 | */ |
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| 272 | private function checkConnectionUp($error_message = '') |
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| 284 | |||
| 285 | /** |
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| 286 | * executeAnonymousQuery |
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| 287 | * |
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| 288 | * Performs a raw SQL query |
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| 289 | * |
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| 290 | * @access public |
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| 291 | * @param string $sql The sql statement to execute. |
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| 292 | * @return ResultHandler|array |
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| 293 | */ |
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| 294 | public function executeAnonymousQuery($sql) |
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| 295 | { |
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| 296 | $ret = pg_send_query($this->getHandler(), $sql); |
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| 297 | |||
| 298 | return $this |
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| 299 | ->testQuery($ret, sprintf("Anonymous query failed '%s'.", $sql)) |
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| 300 | ->getQueryResult($sql) |
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| 301 | ; |
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| 302 | } |
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| 303 | |||
| 304 | /** |
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| 305 | * getQueryResult |
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| 306 | * |
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| 307 | * Get an asynchronous query result. |
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| 308 | * The only reason for the SQL query to be passed as parameter is to throw |
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| 309 | * a meaningful exception when an error is raised. |
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| 310 | * Since it is possible to send several queries at a time, This method can |
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| 311 | * return an array of ResultHandler. |
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| 312 | * |
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| 313 | * @access protected |
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| 314 | * @param string (default null) |
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| 315 | * @throws ConnectionException if no response are available. |
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| 316 | * @throws SqlException if the result is an error. |
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| 317 | * @return ResultHandler|array |
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| 318 | */ |
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| 319 | protected function getQueryResult($sql = null) |
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| 320 | { |
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| 321 | $results = []; |
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| 322 | |||
| 323 | while ($result = pg_get_result($this->getHandler())) { |
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| 324 | $status = pg_result_status($result, \PGSQL_STATUS_LONG); |
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| 325 | |||
| 326 | if ($status !== \PGSQL_COMMAND_OK && $status !== \PGSQL_TUPLES_OK) { |
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| 327 | throw new SqlException($result, $sql); |
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| 328 | } |
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| 329 | |||
| 330 | $results[] = new ResultHandler($result); |
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| 331 | } |
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| 332 | |||
| 333 | if (count($results) === 0) { |
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| 334 | throw new ConnectionException( |
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| 335 | sprintf( |
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| 336 | "There are no waiting results in connection.\nQuery = '%s'.", |
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| 337 | $sql |
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| 338 | ) |
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| 339 | ); |
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| 340 | } |
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| 341 | |||
| 342 | return count($results) === 1 ? $results[0] : $results; |
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| 343 | } |
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| 344 | |||
| 345 | /** |
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| 346 | * escapeIdentifier |
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| 347 | * |
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| 348 | * Escape database object's names. This is different from value escaping |
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| 349 | * as objects names are surrounded by double quotes. API function does |
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| 350 | * provide a nice escaping with -- hopefully -- UTF8 support. |
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| 351 | * |
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| 352 | * @see http://www.postgresql.org/docs/current/static/sql-syntax-lexical.html |
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| 353 | * @access public |
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| 354 | * @param string $string The string to be escaped. |
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| 355 | * @return string the escaped string. |
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| 356 | */ |
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| 357 | public function escapeIdentifier($string) |
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| 358 | { |
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| 359 | return \pg_escape_identifier($this->getHandler(), $string); |
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| 360 | } |
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| 361 | |||
| 362 | /** |
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| 363 | * escapeLiteral |
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| 364 | * |
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| 365 | * Escape a text value. |
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| 366 | * |
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| 367 | * @access public |
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| 368 | * @param string $string The string to be escaped |
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| 369 | * @return string the escaped string. |
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| 370 | */ |
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| 371 | public function escapeLiteral($string) |
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| 372 | { |
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| 373 | return \pg_escape_literal($this->getHandler(), $string); |
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| 374 | } |
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| 375 | |||
| 376 | /** |
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| 377 | * escapeBytea |
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| 378 | * |
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| 379 | * Wrap pg_escape_bytea |
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| 380 | * |
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| 381 | * @access public |
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| 382 | * @param string $word |
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| 383 | * @return string |
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| 384 | */ |
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| 385 | public function escapeBytea($word) |
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| 386 | { |
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| 387 | return pg_escape_bytea($this->getHandler(), $word); |
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| 388 | } |
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| 389 | |||
| 390 | /** |
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| 391 | * unescapeBytea |
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| 392 | * |
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| 393 | * Unescape PostgreSQL bytea. |
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| 394 | * |
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| 395 | * @access public |
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| 396 | * @param string $bytea |
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| 397 | * @return string |
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| 398 | */ |
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| 399 | public function unescapeBytea($bytea) |
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| 400 | { |
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| 401 | return pg_unescape_bytea($bytea); |
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| 402 | } |
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| 403 | |||
| 404 | /** |
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| 405 | * sendQueryWithParameters |
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| 406 | * |
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| 407 | * Execute a asynchronous query with parameters and send the results. |
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| 408 | * |
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| 409 | * @access public |
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| 410 | * @param string $query |
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| 411 | * @param array $parameters |
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| 412 | * @throws SqlException |
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| 413 | * @return ResultHandler query result wrapper |
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| 414 | */ |
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| 415 | public function sendQueryWithParameters($query, array $parameters = []) |
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| 432 | |||
| 433 | /** |
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| 434 | * sendPrepareQuery |
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| 435 | * |
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| 436 | * Send a prepare query statement to the server. |
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| 437 | * |
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| 438 | * @access public |
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| 439 | * @param string $identifier |
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| 440 | * @param string $sql |
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| 441 | * @return Connection $this |
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| 442 | */ |
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| 443 | public function sendPrepareQuery($identifier, $sql) |
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| 444 | { |
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| 455 | |||
| 456 | /** |
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| 457 | * testQueryAndGetResult |
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| 458 | * |
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| 459 | * Factor method to test query return and summon getQueryResult(). |
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| 460 | * |
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| 461 | * @access protected |
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| 462 | * @param mixed $query_return |
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| 463 | * @param string $sql |
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| 464 | * @throws ConnectionException |
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| 465 | * @return Connection $this |
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| 466 | */ |
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| 467 | protected function testQuery($query_return, $sql) |
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| 475 | |||
| 476 | /** |
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| 477 | * sendExecuteQuery |
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| 478 | * |
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| 479 | * Execute a prepared statement. |
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| 480 | * The optional SQL parameter is for debugging purposes only. |
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| 481 | * |
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| 482 | * @access public |
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| 483 | * @param string $identifier |
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| 484 | * @param array $parameters |
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| 485 | * @param string $sql |
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| 486 | * @return ResultHandler |
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| 487 | */ |
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| 488 | public function sendExecuteQuery($identifier, array $parameters = [], $sql = '') |
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| 497 | |||
| 498 | /** |
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| 499 | * getClientEncoding |
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| 500 | * |
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| 501 | * Return the actual client encoding. |
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| 502 | * |
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| 503 | * @access public |
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| 504 | * @return string |
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| 505 | */ |
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| 506 | public function getClientEncoding() |
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| 513 | |||
| 514 | /** |
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| 515 | * setClientEncoding |
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| 516 | * |
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| 517 | * Set client encoding. |
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| 518 | * |
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| 519 | * @access public |
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| 520 | * @param string $encoding |
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| 521 | * @return Connection $this; |
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| 522 | */ |
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| 523 | public function setClientEncoding($encoding) |
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| 531 | |||
| 532 | /** |
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| 533 | * getNotification |
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| 534 | * |
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| 535 | * Get pending notifications. If no notifications are waiting, NULL is |
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| 536 | * returned. Otherwise an associative array containing the optional data |
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| 537 | * and de backend's PID is returned. |
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| 538 | * |
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| 539 | * @access public |
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| 540 | * @return array|null |
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| 541 | */ |
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| 542 | public function getNotification() |
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| 548 | } |
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| 549 |