<?php
/**
* Connection class file
*
* @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 = new \yii\db\dao\Connection(array(
* 'dsn' => $dsn,
* 'username' => $username,
* 'password' => $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 Driver $driver The database driver 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 <qiang.xue@gmail.com>
* @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 [[Driver]] classes.
* The keys of the array are PDO driver names while the values the corresponding
* driver class name or configuration. Please refer to [[\Yii::createObject]] for
* details on how to specify a configuration.
*
* This property is mainly used by [[getDriver()]] when fetching the database schema information.
* You normally do not need to set this property unless you want to use your own
* [[Driver]] class to support DBMS that is not supported by Yii.
*/
public $driverMap = array(
'pgsql' => 'yii\db\dao\pgsql\Driver', // PostgreSQL
'mysqli' => 'yii\db\dao\mysql\Driver', // MySQL
'mysql' => 'yii\db\dao\mysql\Driver', // MySQL
'sqlite' => 'yii\db\dao\sqlite\Driver', // sqlite 3
'sqlite2' => 'yii\db\dao\sqlite\Driver', // sqlite 2
'mssql' => 'yi\db\dao\mssql\Driver', // Mssql driver on windows hosts
'dblib' => 'yii\db\dao\mssql\Driver', // dblib drivers on linux (and maybe others os) hosts
'sqlsrv' => 'yii\db\dao\mssql\Driver', // Mssql
'oci' => 'yii\db\dao\oci\Driver', // Oracle driver
);
/**
* @var Transaction the currently active transaction
*/
private $_transaction;
/**
* @var Driver the database driver
*/
private $_driver;
/**
* 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->_driver = 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 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())
{
$this->open();
return new Command($this, $sql, $params);
}
/**
* Returns the currently active transaction.
* @return Transaction the currently active transaction. Null if no active transaction.
*/
public function getCurrentTransaction()
{
if ($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 Driver the metadata information for the underlying database.
*/
public function getDriver()
{
if ($this->_driver !== null) {
return $this->_driver;
} else {
$driver = $this->getDriverName();
if (isset($this->driverMap[$driver])) {
return $this->_driver = \Yii::createObject($this->driverMap[$driver], $this);
} else {
throw new Exception("Connection does not support reading metadata for '$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->getDriver()->getQueryBuilder();
}
/**
* Obtains the metadata for the named table.
* @param string $name table name. The table name may contain schema name if any. Do not quote the table name.
* @param boolean $refresh whether to reload the table schema even if it is found in the cache.
* @return TableSchema table metadata. Null if the named table does not exist.
*/
public function getTableSchema($name, $refresh = false)
{
return $this->getDriver()->getTableSchema($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 = '')
{
$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 ? $this->getDriver()->quoteSimpleTableName($name) : $this->getDriver()->quoteTableName($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 ? $this->getDriver()->quoteSimpleColumnName($name) : $this->getDriver()->quoteColumnName($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);
}
}