* @link http://www.yiiframework.com/ * @copyright Copyright © 2008-2012 Yii Software LLC * @license http://www.yiiframework.com/license/ */ namespace yii\db\dao; use yii\db\Exception; /** * Connection represents a connection to a database via [PDO](http://www.php.net/manual/en/ref.pdo.php). * * Connection works together with [[Command]], [[DataReader]] and [[Transaction]] * to provide data access to various DBMS in a common set of APIs. They are a thin wrapper * of the [[PDO PHP extension]](http://www.php.net/manual/en/ref.pdo.php). * * To establish a DB connection, set [[dsn]], [[username]] and [[password]], and then * call [[open]] or set [[active]] to be true. * * The following example shows how to create a Connection instance and establish * the DB connection: * * ~~~ * $connection = \yii\db\dao\Connection::newInstance($dsn, $username, $password); * $connection->active = true; // same as: $connection->open(); * ~~~ * * After the DB connection is established, one can execute SQL statements like the following: * * ~~~ * $command = $connection->createCommand('SELECT * FROM tbl_post'); * $posts = $command->queryAll(); * $command = $connection->createCommand('UPDATE tbl_post SET status=1'); * $command->execute(); * ~~~ * * One can also do prepared SQL execution and bind parameters to the prepared SQL. * When the parameters are coming from user input, you should use this approach * to prevent SQL injection attacks. The following is an example: * * ~~~ * $command = $connection->createCommand('SELECT * FROM tbl_post WHERE id=:id'); * $command->bindValue(':id', $_GET['id']); * $post = $command->query(); * ~~~ * * For more information about how to perform various DB queries, please refer to [[Command]]. * * If the underlying DBMS supports transactions, you can perform transactional SQL queries * like the following: * * ~~~ * $transaction = $connection->beginTransaction(); * try { * $connection->createCommand($sql1)->execute(); * $connection->createCommand($sql2)->execute(); * // ... executing other SQL statements ... * $transaction->commit(); * } * catch(Exception $e) { * $transaction->rollBack(); * } * ~~~ * * Connection is often used as an [[\yii\base\ApplicationComponent|application component]] and configured in the application * configuration like the following: * * ~~~ * array( * 'components' => array( * 'db' => array( * 'class' => '\yii\db\dao\Connection', * 'dsn' => 'mysql:host=127.0.0.1;dbname=demo', * 'username' => 'root', * 'password' => '', * 'charset' => 'utf8', * ), * ), * ) * ~~~ * * @property boolean $active Whether the DB connection is established. * @property Transaction $currentTransaction The currently active transaction. Null if no active transaction. * @property Schema $schema The database schema for the current connection. * @property QueryBuilder $queryBuilder The query builder. * @property string $lastInsertID The row ID of the last row inserted, or the last value retrieved from the sequence object. * @property string $driverName Name of the DB driver currently being used. * @property string $clientVersion The version information of the DB driver. * @property array $stats The statistical results of SQL executions. * * @author Qiang Xue * @since 2.0 */ class Connection extends \yii\base\ApplicationComponent { /** * @var string the Data Source Name, or DSN, contains the information required to connect to the database. * Please refer to the [PHP manual](http://www.php.net/manual/en/function.PDO-construct.php) on * the format of the DSN string. * @see charset */ public $dsn; /** * @var string the username for establishing DB connection. Defaults to empty string. */ public $username = ''; /** * @var string the password for establishing DB connection. Defaults to empty string. */ public $password = ''; /** * @var array PDO attributes (name=>value) that should be set when calling [[open]] * to establish a DB connection. Please refer to the * [PHP manual](http://www.php.net/manual/en/function.PDO-setAttribute.php) for * details about available attributes. */ public $attributes; /** * @var \PDO the PHP PDO instance associated with this DB connection. * This property is mainly managed by [[open]] and [[close]] methods. * When a DB connection is active, this property will represent a PDO instance; * otherwise, it will be null. */ public $pdo; /** * @var integer number of seconds that table metadata can remain valid in cache. * Defaults to -1, meaning schema caching is disabled. * Use 0 to indicate that the cached data will never expire. * * Note that in order to enable schema caching, a valid cache component as specified * by [[schemaCacheID]] must be enabled. * @see schemaCachingExclude * @see schemaCacheID */ public $schemaCachingDuration = -1; /** * @var array list of tables whose metadata should NOT be cached. Defaults to empty array. * The table names may contain schema prefix, if any. Do not quote the table names. * @see schemaCachingDuration */ public $schemaCachingExclude = array(); /** * @var string the ID of the cache application component that is used to cache the table metadata. * Defaults to 'cache'. * @see schemaCachingDuration */ public $schemaCacheID = 'cache'; /** * @var integer number of seconds that query results can remain valid in cache. * Defaults to -1, meaning query caching is disabled. * Use 0 to indicate that the cached data will never expire. * * Note that in order to enable query caching, a valid cache component as specified * by [[queryCacheID]] must be enabled. * * The method [[cache()]] is provided as a convenient way of setting this property * and [[queryCachingDependency]] on the fly. * * @see cache * @see queryCachingDependency * @see queryCacheID */ public $queryCachingDuration = -1; /** * @var \yii\caching\Dependency the dependency that will be used when saving query results into cache. * Defaults to null, meaning no dependency. * @see queryCachingDuration */ public $queryCachingDependency; /** * @var integer the number of SQL statements that need to be cached when they are executed next. * Defaults to 0, meaning the query result of the next SQL statement will NOT be cached. * Note that each time after executing a SQL statement (whether executed on DB server or fetched from * query cache), this property will be reduced by 1 until 0. * @see queryCachingDuration */ public $queryCachingCount = 0; /** * @var string the ID of the cache application component that is used for query caching. * Defaults to 'cache'. * @see queryCachingDuration */ public $queryCacheID = 'cache'; /** * @var string the charset used for database connection. The property is only used * for MySQL and PostgreSQL databases. Defaults to null, meaning using default charset * as specified by the database. * * Note that if you're using GBK or BIG5 then it's highly recommended to * update to PHP 5.3.6+ and to specify charset via DSN like * 'mysql:dbname=mydatabase;host=127.0.0.1;charset=GBK;'. */ public $charset; /** * @var boolean whether to turn on prepare emulation. Defaults to false, meaning PDO * will use the native prepare support if available. For some databases (such as MySQL), * this may need to be set true so that PDO can emulate the prepare support to bypass * the buggy native prepare support. * The default value is null, which means the PDO ATTR_EMULATE_PREPARES value will not be changed. */ public $emulatePrepare; /** * @var boolean whether to enable profiling for the SQL statements being executed. * Defaults to false. This should be mainly enabled and used during development * to find out the bottleneck of SQL executions. * @see getStats */ public $enableProfiling = false; /** * @var string the default prefix for table names. Defaults to null, meaning not using table prefix. * By setting this property, any token like '{{TableName}}' in [[Command::sql]] will * be replaced with 'prefixTableName', where 'prefix' refers to this property value. * For example, '{{post}}' becomes 'tbl_post', if 'tbl_' is set as the table prefix. * * Note that if you set this property to be an empty string, then '{{post}}' will be replaced * with 'post'. */ public $tablePrefix; /** * @var array a list of SQL statements that should be executed right after the DB connection is established. */ public $initSQLs; /** * @var array mapping between PDO driver names and [[Schema]] classes. * The keys of the array are PDO driver names while the values the corresponding * schema class name or configuration. Please refer to [[\Yii::createObject]] for * details on how to specify a configuration. * * This property is mainly used by [[getSchema]] when fetching the database schema information. * You normally do not need to set this property unless you want to use your own * [[Schema]] class to support DBMS that is not supported by Yii. */ public $schemaMap = array( 'pgsql' => '\yii\db\dao\pgsql\Schema', // PostgreSQL 'mysqli' => '\yii\db\dao\mysql\Schema', // MySQL 'mysql' => '\yii\db\dao\mysql\Schema', // MySQL 'sqlite' => '\yii\db\dao\sqlite\Schema', // sqlite 3 'sqlite2' => '\yii\db\dao\sqlite\Schema', // sqlite 2 'mssql' => '\yii\db\dao\mssql\Schema', // Mssql driver on windows hosts 'dblib' => '\yii\db\dao\mssql\Schema', // dblib drivers on linux (and maybe others os) hosts 'sqlsrv' => '\yii\db\dao\mssql\Schema', // Mssql 'oci' => '\yii\db\dao\oci\Schema', // Oracle driver ); /** * @var Transaction the currently active transaction */ private $_transaction; /** * @var Schema the database schema */ private $_schema; /** * Constructor. * Note, the DB connection is not established when this connection * instance is created. You may set [[active]] to be true or call [[open]] * to establish the connection. * @param string $dsn the Data Source Name, or DSN, contains the information * required to connect to the database. * @param string $username the user name for the DSN string. * @param string $password the password for the DSN string. * @see http://www.php.net/manual/en/function.PDO-construct.php */ public function __construct($dsn = '', $username = '', $password = '') { $this->dsn = $dsn; $this->username = $username; $this->password = $password; } /** * Closes the connection when this component is being serialized. * @return array */ public function __sleep() { $this->close(); return array_keys(get_object_vars($this)); } /** * Returns a list of available PDO drivers. * @return array list of available PDO drivers * @see http://www.php.net/manual/en/function.PDO-getAvailableDrivers.php */ public static function getAvailableDrivers() { return \PDO::getAvailableDrivers(); } /** * Returns a value indicating whether the DB connection is established. * @return boolean whether the DB connection is established */ public function getActive() { return $this->pdo !== null; } /** * Opens or closes the DB connection. * @param boolean $value whether to open or close the DB connection * @throws Exception if there is any error when establishing the connection */ public function setActive($value) { $value ? $this->open() : $this->close(); } /** * Sets the parameters about query caching. * This method is provided as a shortcut to setting three properties that are related * with query caching: [[queryCachingDuration]], [[queryCachingDependency]] and * [[queryCachingCount]]. * @param integer $duration the number of seconds that query results may remain valid in cache. * See [[queryCachingDuration]] for more details. * @param \yii\caching\Dependency $dependency the dependency for the cached query result. * See [[queryCachingDependency]] for more details. * @param integer $queryCount the number of SQL queries that need to be cached after calling this method. * See [[queryCachingCount]] for more details. * @return Connection the connection instance itself. */ public function cache($duration = 300, $dependency = null, $queryCount = 1) { $this->queryCachingDuration = $duration; $this->queryCachingDependency = $dependency; $this->queryCachingCount = $queryCount; return $this; } /** * Establishes a DB connection. * It does nothing if a DB connection has already been established. * @throws Exception if connection fails */ public function open() { if ($this->pdo === null) { if (empty($this->dsn)) { throw new Exception('Connection.dsn cannot be empty.'); } try { \Yii::trace('Opening DB connection: ' . $this->dsn, __CLASS__); $this->pdo = $this->createPdoInstance(); $this->initConnection($this->pdo); } catch (\PDOException $e) { \Yii::error("Failed to open DB connection ({$this->dsn}): " . $e->getMessage(), __CLASS__); $message = YII_DEBUG ? 'Failed to open DB connection: ' . $e->getMessage() : 'Failed to open DB connection.'; throw new Exception($message, (int)$e->getCode(), $e->errorInfo); } } } /** * Closes the currently active DB connection. * It does nothing if the connection is already closed. */ public function close() { if ($this->pdo !== null) { \Yii::trace('Closing DB connection: ' . $this->dsn, __CLASS__); $this->pdo = null; $this->_schema = null; $this->_transaction = null; } } /** * Creates the PDO instance. * This method is called by [[open]] to establish a DB connection. * The default implementation will create a PHP PDO instance. * You may override this method if the default PDO needs to be adapted for certain DBMS. * @return \PDO the pdo instance */ protected function createPdoInstance() { $pdoClass = '\PDO'; if (($pos = strpos($this->dsn, ':')) !== false) { $driver = strtolower(substr($this->dsn, 0, $pos)); if ($driver === 'mssql' || $driver === 'dblib' || $driver === 'sqlsrv') { $pdoClass = 'mssql\PDO'; } } return new $pdoClass($this->dsn, $this->username, $this->password, $this->attributes); } /** * Initializes the DB connection. * This method is invoked right after the DB connection is established. * The default implementation sets the database [[charset]] and executes SQLs specified * in [[initSQLs]]. */ protected function initConnection() { $this->pdo->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION); if ($this->emulatePrepare !== null && constant('\PDO::ATTR_EMULATE_PREPARES')) { $this->pdo->setAttribute(\PDO::ATTR_EMULATE_PREPARES, $this->emulatePrepare); } if ($this->charset !== null && in_array($this->getDriverName(), array('pgsql', 'mysql', 'mysqli'))) { $this->pdo->exec('SET NAMES ' . $this->pdo->quote($this->charset)); } if (!empty($this->initSQLs)) { foreach ($this->initSQLs as $sql) { $this->pdo->exec($sql); } } } /** * Creates a command for execution. * @param mixed $query the DB query to be executed. This can be: * * - a string representing the SQL statement to be executed * - a [[Query]] object representing the SQL query * - an array that will be used to initialize [[Query]] * - null (default) if the query needs to be built using query builder methods next. * @return Command the DB command */ public function createCommand($query = null) { $this->open(); return new Command($this, $query); } /** * Returns the currently active transaction. * @return Transaction the currently active transaction. Null if no active transaction. */ public function getCurrentTransaction() { if ($this->_transaction !== null && $this->_transaction->active) { return $this->_transaction; } else { return null; } } /** * Starts a transaction. * @return Transaction the transaction initiated */ public function beginTransaction() { \Yii::trace('Starting transaction', __CLASS__); $this->open(); $this->pdo->beginTransaction(); return $this->_transaction = new Transaction($this); } /** * Returns the metadata information for the underlying database. * @return Schema the metadata information for the underlying database. */ public function getSchema() { if ($this->_schema !== null) { return $this->_schema; } else { $driver = $this->getDriverName(); if (isset($this->schemaMap[$driver])) { return $this->_schema = \Yii::createObject($this->schemaMap[$driver], $this); } else { throw new Exception("Connection does not support reading schema for '$driver' database."); } } } /** * Returns the query builder for the current DB connection. * @return QueryBuilder the query builder for the current DB connection. */ public function getQueryBuilder() { return $this->getSchema()->getQueryBuilder(); } /** * Returns the ID of the last inserted row or sequence value. * @param string $sequenceName name of the sequence object (required by some DBMS) * @return string the row ID of the last row inserted, or the last value retrieved from the sequence object * @see http://www.php.net/manual/en/function.PDO-lastInsertId.php */ public function getLastInsertID($sequenceName = '') { $this->open(); return $this->pdo->lastInsertId($sequenceName); } /** * Quotes a string value for use in a query. * Note that if the parameter is not a string, it will be returned without change. * @param string $str string to be quoted * @return string the properly quoted string * @see http://www.php.net/manual/en/function.PDO-quote.php */ public function quoteValue($str) { if (!is_string($str)) { return $str; } $this->open(); if (($value = $this->pdo->quote($str)) !== false) { return $value; } else { // the driver doesn't support quote (e.g. oci) return "'" . addcslashes(str_replace("'", "''", $str), "\000\n\r\\\032") . "'"; } } /** * Quotes a table name for use in a query. * If the table name contains schema prefix, the prefix will also be properly quoted. * @param string $name table name * @param boolean $simple if this is true, then the method will assume $name is a table name without schema prefix. * @return string the properly quoted table name */ public function quoteTableName($name, $simple = false) { return $simple ? $this->getSchema()->quoteSimpleTableName($name) : $this->getSchema()->quoteTableName($name); } /** * Quotes a column name for use in a query. * If the column name contains table prefix, the prefix will also be properly quoted. * @param string $name column name * @param boolean $simple if this is true, then the method will assume $name is a column name without table prefix. * @return string the properly quoted column name */ public function quoteColumnName($name, $simple = false) { return $simple ? $this->getSchema()->quoteSimpleColumnName($name) : $this->getSchema()->quoteColumnName($name); } /** * Prefixes table names in a SQL statement with [[tablePrefix]]. * By calling this method, tokens like '{{TableName}}' in the given SQL statement will * be replaced with 'prefixTableName', where 'prefix' refers to [[tablePrefix]]. * Note that if [[tablePrefix]] is null, this method will do nothing. * @param string $sql the SQL statement whose table names need to be prefixed with [[tablePrefix]]. * @return string the expanded SQL statement * @see tablePrefix */ public function expandTablePrefix($sql) { if ($this->tablePrefix !== null && strpos($sql, '{{') !== false) { return preg_replace('/{{(.*?)}}/', $this->tablePrefix . '\1', $sql); } else { return $sql; } } /** * Determines the PDO type for the give PHP data type. * @param string $type The PHP type (obtained by `gettype()` call). * @return integer the corresponding PDO type * @see http://www.php.net/manual/en/pdo.constants.php */ public function getPdoType($type) { static $typeMap = array( 'boolean' => \PDO::PARAM_BOOL, 'integer' => \PDO::PARAM_INT, 'string' => \PDO::PARAM_STR, 'NULL' => \PDO::PARAM_NULL, ); return isset($typeMap[$type]) ? $typeMap[$type] : \PDO::PARAM_STR; } /** * Returns the name of the DB driver for the current [[dsn]]. * @return string name of the DB driver */ public function getDriverName() { if (($pos = strpos($this->dsn, ':')) !== false) { return strtolower(substr($this->dsn, 0, $pos)); } else { return strtolower($this->getAttribute(\PDO::ATTR_DRIVER_NAME)); } } /** * Obtains a specific DB connection attribute information. * @param integer $name the attribute to be queried * @return mixed the corresponding attribute information * @see http://www.php.net/manual/en/function.PDO-getAttribute.php */ public function getAttribute($name) { $this->open(); return $this->pdo->getAttribute($name); } /** * Sets an attribute on the database connection. * @param integer $name the attribute to be set * @param mixed $value the attribute value * @see http://www.php.net/manual/en/function.PDO-setAttribute.php */ public function setAttribute($name, $value) { $this->open(); $this->pdo->setAttribute($name, $value); } /** * Returns the statistical results of SQL executions. * The results returned include the number of SQL statements executed and * the total time spent. * In order to use this method, [[enableProfiling]] has to be set true. * @return array the first element indicates the number of SQL statements executed, * and the second element the total time spent in SQL execution. * @see \yii\logging\Logger::getProfiling() */ public function getStats() { $logger = \Yii::getLogger(); $timings = $logger->getProfiling(array('yii\db\dao\Command::query', 'yii\db\dao\Command::execute')); $count = count($timings); $time = 0; foreach ($timings as $timing) { $time += $timing[1]; } return array($count, $time); } }