$dsn, * 'username' => $username, * 'password' => $password, * )); * $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 application component and configured in the application * configuration like the following: * * ~~~ * array( * 'components' => array( * 'db' => array( * 'class' => '\yii\db\Connection', * 'dsn' => 'mysql:host=127.0.0.1;dbname=demo', * 'username' => 'root', * 'password' => '', * 'charset' => 'utf8', * ), * ), * ) * ~~~ * * @property boolean $isActive Whether the DB connection is established. This property is read-only. * @property Transaction $transaction The currently active transaction. Null if no active transaction. * @property Schema $schema The database schema information 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 array $querySummary The statistical results of SQL queries. * * @author Qiang Xue * @since 2.0 */ class Connection extends Component { /** * @event Event an event that is triggered after a DB connection is established */ const EVENT_AFTER_OPEN = 'afterOpen'; /** * @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 boolean whether to enable schema caching. * Note that in order to enable truly schema caching, a valid cache component as specified * by [[schemaCache]] must be enabled and [[enableSchemaCache]] must be set true. * @see schemaCacheDuration * @see schemaCacheExclude * @see schemaCache */ public $enableSchemaCache = false; /** * @var integer number of seconds that table metadata can remain valid in cache. * Use 0 to indicate that the cached data will never expire. * @see enableSchemaCache */ public $schemaCacheDuration = 3600; /** * @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 enableSchemaCache */ public $schemaCacheExclude = array(); /** * @var Cache|string the cache object or the ID of the cache application component that * is used to cache the table metadata. * @see enableSchemaCache */ public $schemaCache = 'cache'; /** * @var boolean whether to enable query caching. * Note that in order to enable query caching, a valid cache component as specified * by [[queryCache]] must be enabled and [[enableQueryCache]] must be set true. * * Methods [[beginCache()]] and [[endCache()]] can be used as shortcuts to turn on * and off query caching on the fly. * @see queryCacheDuration * @see queryCache * @see queryCacheDependency * @see beginCache() * @see endCache() */ public $enableQueryCache = false; /** * @var integer number of seconds that query results can remain valid in cache. * Defaults to 3600, meaning 3600 seconds, or one hour. * Use 0 to indicate that the cached data will never expire. * @see enableQueryCache */ public $queryCacheDuration = 3600; /** * @var \yii\caching\Dependency the dependency that will be used when saving query results into cache. * Defaults to null, meaning no dependency. * @see enableQueryCache */ public $queryCacheDependency; /** * @var Cache|string the cache object or the ID of the cache application component * that is used for query caching. * @see enableQueryCache */ public $queryCache = '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 string the common prefix or suffix for table names. If a table name is given * as `{{%TableName}}`, then the percentage character `%` will be replaced with this * property value. For example, `{{%post}}` becomes `{{tbl_post}}` if this property is * set as `"tbl_"`. */ public $tablePrefix; /** * @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\pgsql\Schema', // PostgreSQL 'mysqli' => 'yii\db\mysql\Schema', // MySQL 'mysql' => 'yii\db\mysql\Schema', // MySQL 'sqlite' => 'yii\db\sqlite\Schema', // sqlite 3 'sqlite2' => 'yii\db\sqlite\Schema', // sqlite 2 'sqlsrv' => 'yii\db\mssql\Schema', // newer MSSQL driver on MS Windows hosts 'oci' => 'yii\db\oci\Schema', // Oracle driver 'mssql' => 'yii\db\mssql\Schema', // older MSSQL driver on MS Windows hosts 'dblib' => 'yii\db\mssql\Schema', // dblib drivers on GNU/Linux (and maybe other OSes) hosts ); /** * @var Transaction the currently active transaction */ private $_transaction; /** * @var Schema the database schema */ private $_schema; /** * Returns a value indicating whether the DB connection is established. * @return boolean whether the DB connection is established */ public function getIsActive() { return $this->pdo !== null; } /** * Turns on query caching. * This method is provided as a shortcut to setting two properties that are related * with query caching: [[queryCacheDuration]] and [[queryCacheDependency]]. * @param integer $duration the number of seconds that query results may remain valid in cache. * If not set, it will use the value of [[queryCacheDuration]]. See [[queryCacheDuration]] for more details. * @param \yii\caching\Dependency $dependency the dependency for the cached query result. * See [[queryCacheDependency]] for more details. */ public function beginCache($duration = null, $dependency = null) { $this->enableQueryCache = true; if ($duration !== null) { $this->queryCacheDuration = $duration; } $this->queryCacheDependency = $dependency; } /** * Turns off query caching. */ public function endCache() { $this->enableQueryCache = false; } /** * Establishes a DB connection. * It does nothing if a DB connection has already been established. * @throws Exception if connection fails */ public function open() { if ($this->pdo === null) { if (empty($this->dsn)) { throw new InvalidConfigException('Connection::dsn cannot be empty.'); } $token = 'Opening DB connection: ' . $this->dsn; try { Yii::trace($token, __METHOD__); Yii::beginProfile($token, __METHOD__); $this->pdo = $this->createPdoInstance(); $this->initConnection(); Yii::endProfile($token, __METHOD__); } catch (\PDOException $e) { Yii::endProfile($token, __METHOD__); throw new Exception($e->getMessage(), $e->errorInfo, (int)$e->getCode(), $e); } } } /** * Closes the currently active DB connection. * It does nothing if the connection is already closed. */ public function close() { if ($this->pdo !== null) { Yii::trace('Closing DB connection: ' . $this->dsn, __METHOD__); $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 = 'yii\db\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 turns on `PDO::ATTR_EMULATE_PREPARES` * if [[emulatePrepare]] is true, and sets the database [[charset]] if it is not empty. * It then triggers an [[EVENT_AFTER_OPEN]] event. */ 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)); } $this->trigger(self::EVENT_AFTER_OPEN); } /** * Creates a command for execution. * @param string $sql the SQL statement to be executed * @param array $params the parameters to be bound to the SQL statement * @return Command the DB command */ public function createCommand($sql = null, $params = array()) { $this->open(); $command = new Command(array( 'db' => $this, 'sql' => $sql, )); return $command->bindValues($params); } /** * Returns the currently active transaction. * @return Transaction the currently active transaction. Null if no active transaction. */ public function getTransaction() { return $this->_transaction && $this->_transaction->isActive ? $this->_transaction : null; } /** * Starts a transaction. * @return Transaction the transaction initiated */ public function beginTransaction() { $this->open(); $this->_transaction = new Transaction(array( 'db' => $this, )); $this->_transaction->begin(); return $this->_transaction; } /** * Returns the schema information for the database opened by this connection. * @return Schema the schema information for the database opened by this connection. * @throws NotSupportedException if there is no support for the current driver type */ public function getSchema() { if ($this->_schema !== null) { return $this->_schema; } else { $driver = $this->getDriverName(); if (isset($this->schemaMap[$driver])) { $this->_schema = Yii::createObject($this->schemaMap[$driver]); $this->_schema->db = $this; return $this->_schema; } else { throw new NotSupportedException("Connection does not support reading schema information for '$driver' DBMS."); } } } /** * 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(); } /** * Obtains the schema information for the named table. * @param string $name table name. * @param boolean $refresh whether to reload the table schema even if it is found in the cache. * @return TableSchema table schema information. Null if the named table does not exist. */ public function getTableSchema($name, $refresh = false) { return $this->getSchema()->getTableSchema($name, $refresh); } /** * 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 = '') { return $this->getSchema()->getLastInsertID($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) { return $this->getSchema()->quoteValue($str); } /** * Quotes a table name for use in a query. * If the table name contains schema prefix, the prefix will also be properly quoted. * If the table name is already quoted or contains special characters including '(', '[[' and '{{', * then this method will do nothing. * @param string $name table name * @return string the properly quoted table name */ public function quoteTableName($name) { return $this->getSchema()->quoteTableName($name); } /** * Quotes a column name for use in a query. * If the column name contains prefix, the prefix will also be properly quoted. * If the column name is already quoted or contains special characters including '(', '[[' and '{{', * then this method will do nothing. * @param string $name column name * @return string the properly quoted column name */ public function quoteColumnName($name) { return $this->getSchema()->quoteColumnName($name); } /** * Processes a SQL statement by quoting table and column names that are enclosed within double brackets. * Tokens enclosed within double curly brackets are treated as table names, while * tokens enclosed within double square brackets are column names. They will be quoted accordingly. * Also, the percentage character "%" at the beginning or ending of a table name will be replaced * with [[tablePrefix]]. * @param string $sql the SQL to be quoted * @return string the quoted SQL */ public function quoteSql($sql) { $db = $this; return preg_replace_callback('/(\\{\\{(%?[\w\-\. ]+%?)\\}\\}|\\[\\[([\w\-\. ]+)\\]\\])/', function ($matches) use ($db) { if (isset($matches[3])) { return $db->quoteColumnName($matches[3]); } else { return str_replace('%', $db->tablePrefix, $db->quoteTableName($matches[2])); } }, $sql); } /** * Returns the name of the DB driver for the current [[dsn]]. * @return string name of the DB driver */ public function getDriverName() { if (($pos = strpos($this->dsn, ':')) !== false) { return strtolower(substr($this->dsn, 0, $pos)); } else { $this->open(); return strtolower($this->pdo->getAttribute(PDO::ATTR_DRIVER_NAME)); } } }