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Class yii\db\Connection

Inheritanceyii\db\Connection » yii\base\Component » yii\base\BaseObject
Implementsyii\base\Configurable
Available since version2.0
Source Code https://github.com/yiisoft/yii2/blob/master/framework/db/Connection.php

Connection represents a connection to a database via PDO.

Connection works together with yii\db\Command, yii\db\DataReader and yii\db\Transaction to provide data access to various DBMS in a common set of APIs. They are a thin wrapper of the PDO PHP extension.

Connection supports database replication and read-write splitting. In particular, a Connection component can be configured with multiple $masters and $slaves. It will do load balancing and failover by choosing appropriate servers. It will also automatically direct read operations to the slaves and write operations to the masters.

To establish a DB connection, set $dsn, $username and $password, and then call open() to connect to the database server. The current state of the connection can be checked using $isActive.

The following example shows how to create a Connection instance and establish the DB connection:

$connection = new \yii\db\Connection([
    'dsn' => $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 post');
$posts = $command->queryAll();
$command = $connection->createCommand('UPDATE 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 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 yii\db\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();
}

You also can use shortcut for the above like the following:

$connection->transaction(function () {
    $order = new Order($customer);
    $order->save();
    $order->addItems($items);
});

If needed you can pass transaction isolation level as a second parameter:

$connection->transaction(function (Connection $db) {
    //return $db->...
}, Transaction::READ_UNCOMMITTED);

Connection is often used as an application component and configured in the application configuration like the following:

'components' => [
    'db' => [
        'class' => '\yii\db\Connection',
        'dsn' => 'mysql:host=127.0.0.1;dbname=demo',
        'username' => 'root',
        'password' => '',
        'charset' => 'utf8',
    ],
],

Public Properties

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Property Type Description Defined By
$attributes array PDO attributes (name => value) that should be set when calling open() to establish a DB connection. yii\db\Connection
$behaviors yii\base\Behavior[] List of behaviors attached to this component. yii\base\Component
$charset string|null The charset used for database connection. yii\db\Connection
$commandClass string The class used to create new database yii\db\Command objects. yii\db\Connection
$commandMap array Mapping between PDO driver names and yii\db\Command classes. yii\db\Connection
$driverName string Name of the DB driver. yii\db\Connection
$dsn string The Data Source Name, or DSN, contains the information required to connect to the database. yii\db\Connection
$emulatePrepare boolean|null Whether to turn on prepare emulation. yii\db\Connection
$enableLogging boolean Whether to enable logging of database queries. yii\db\Connection
$enableProfiling boolean Whether to enable profiling of opening database connection and database queries. yii\db\Connection
$enableQueryCache boolean Whether to enable query caching. yii\db\Connection
$enableSavepoint boolean Whether to enable savepoint. yii\db\Connection
$enableSchemaCache boolean Whether to enable schema caching. yii\db\Connection
$enableSlaves boolean Whether to enable read/write splitting by using $slaves to read data. yii\db\Connection
$isActive boolean Whether the DB connection is established. yii\db\Connection
$isSybase boolean If the database connected via pdo_dblib is SyBase. yii\db\Connection
$lastInsertID string The row ID of the last row inserted, or the last value retrieved from the sequence object. yii\db\Connection
$master yii\db\Connection The currently active master connection. yii\db\Connection
$masterConfig array The configuration that should be merged with every master configuration listed in $masters. yii\db\Connection
$masterPdo PDO The PDO instance for the currently active master connection. yii\db\Connection
$masters array List of master connection configurations. yii\db\Connection
$password string|null The password for establishing DB connection. yii\db\Connection
$pdo PDO|null The PHP PDO instance associated with this DB connection. yii\db\Connection
$pdoClass string|null Custom PDO wrapper class. yii\db\Connection
$queryBuilder yii\db\QueryBuilder The query builder for the current DB connection. yii\db\Connection
$queryCache yii\caching\CacheInterface|string The cache object or the ID of the cache application component that is used for query caching. yii\db\Connection
$queryCacheDuration integer The default number of seconds that query results can remain valid in cache. yii\db\Connection
$schema yii\db\Schema The schema information for the database opened by this connection. yii\db\Connection
$schemaCache yii\caching\CacheInterface|string The cache object or the ID of the cache application component that is used to cache the table metadata. yii\db\Connection
$schemaCacheDuration integer Number of seconds that table metadata can remain valid in cache. yii\db\Connection
$schemaCacheExclude array List of tables whose metadata should NOT be cached. yii\db\Connection
$schemaMap array Mapping between PDO driver names and yii\db\Schema classes. yii\db\Connection
$serverRetryInterval integer The retry interval in seconds for dead servers listed in $masters and $slaves. yii\db\Connection
$serverStatusCache yii\caching\CacheInterface|string|false The cache object or the ID of the cache application component that is used to store the health status of the DB servers specified in $masters and $slaves. yii\db\Connection
$serverVersion string Server version as a string. yii\db\Connection
$shuffleMasters boolean Whether to shuffle $masters before getting one. yii\db\Connection
$slave yii\db\Connection The currently active slave connection. yii\db\Connection
$slaveConfig array The configuration that should be merged with every slave configuration listed in $slaves. yii\db\Connection
$slavePdo PDO The PDO instance for the currently active slave connection. yii\db\Connection
$slaves array List of slave connection configurations. yii\db\Connection
$tablePrefix string The common prefix or suffix for table names. yii\db\Connection
$transaction yii\db\Transaction|null The currently active transaction. yii\db\Connection
$username string|null The username for establishing DB connection. yii\db\Connection

Public Methods

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Method Description Defined By
__call() Calls the named method which is not a class method. yii\base\Component
__clone() Reset the connection after cloning. yii\db\Connection
__construct() Constructor. yii\base\BaseObject
__get() Returns the value of a component property. yii\base\Component
__isset() Checks if a property is set, i.e. defined and not null. yii\base\Component
__set() Sets the value of a component property. yii\base\Component
__sleep() Close the connection before serializing. yii\db\Connection
__unset() Sets a component property to be null. yii\base\Component
attachBehavior() Attaches a behavior to this component. yii\base\Component
attachBehaviors() Attaches a list of behaviors to the component. yii\base\Component
beginTransaction() Starts a transaction. yii\db\Connection
behaviors() Returns a list of behaviors that this component should behave as. yii\base\Component
cache() Uses query cache for the queries performed with the callable. yii\db\Connection
canGetProperty() Returns a value indicating whether a property can be read. yii\base\Component
canSetProperty() Returns a value indicating whether a property can be set. yii\base\Component
className() Returns the fully qualified name of this class. yii\base\BaseObject
close() Closes the currently active DB connection. yii\db\Connection
createCommand() Creates a command for execution. yii\db\Connection
detachBehavior() Detaches a behavior from the component. yii\base\Component
detachBehaviors() Detaches all behaviors from the component. yii\base\Component
ensureBehaviors() Makes sure that the behaviors declared in behaviors() are attached to this component. yii\base\Component
getBehavior() Returns the named behavior object. yii\base\Component
getBehaviors() Returns all behaviors attached to this component. yii\base\Component
getDriverName() Returns the name of the DB driver. Based on the the current $dsn, in case it was not set explicitly by an end user. yii\db\Connection
getIsActive() Returns a value indicating whether the DB connection is established. yii\db\Connection
getLastInsertID() Returns the ID of the last inserted row or sequence value. yii\db\Connection
getMaster() Returns the currently active master connection. yii\db\Connection
getMasterPdo() Returns the PDO instance for the currently active master connection. yii\db\Connection
getQueryBuilder() Returns the query builder for the current DB connection. yii\db\Connection
getSchema() Returns the schema information for the database opened by this connection. yii\db\Connection
getServerVersion() Returns a server version as a string comparable by \version_compare(). yii\db\Connection
getSlave() Returns the currently active slave connection. yii\db\Connection
getSlavePdo() Returns the PDO instance for the currently active slave connection. yii\db\Connection
getTableSchema() Obtains the schema information for the named table. yii\db\Connection
getTransaction() Returns the currently active transaction. yii\db\Connection
hasEventHandlers() Returns a value indicating whether there is any handler attached to the named event. yii\base\Component
hasMethod() Returns a value indicating whether a method is defined. yii\base\Component
hasProperty() Returns a value indicating whether a property is defined for this component. yii\base\Component
init() Initializes the object. yii\base\BaseObject
noCache() Disables query cache temporarily. yii\db\Connection
off() Detaches an existing event handler from this component. yii\base\Component
on() Attaches an event handler to an event. yii\base\Component
open() Establishes a DB connection. yii\db\Connection
quoteColumnName() Quotes a column name for use in a query. yii\db\Connection
quoteSql() Processes a SQL statement by quoting table and column names that are enclosed within double brackets. yii\db\Connection
quoteTableName() Quotes a table name for use in a query. yii\db\Connection
quoteValue() Quotes a string value for use in a query. yii\db\Connection
setDriverName() Changes the current driver name. yii\db\Connection
setQueryBuilder() Can be used to set yii\db\QueryBuilder configuration via Connection configuration array. yii\db\Connection
transaction() Executes callback provided in a transaction. yii\db\Connection
trigger() Triggers an event. yii\base\Component
useMaster() Executes the provided callback by using the master connection. yii\db\Connection

Protected Methods

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Method Description Defined By
createPdoInstance() Creates the PDO instance. yii\db\Connection
initConnection() Initializes the DB connection. yii\db\Connection
openFromPool() Opens the connection to a server in the pool. yii\db\Connection
openFromPoolSequentially() Opens the connection to a server in the pool. yii\db\Connection

Events

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Event Type Description Defined By
EVENT_AFTER_OPEN yii\base\Event An event that is triggered after a DB connection is established yii\db\Connection
EVENT_BEGIN_TRANSACTION yii\base\Event An event that is triggered right before a top-level transaction is started yii\db\Connection
EVENT_COMMIT_TRANSACTION yii\base\Event An event that is triggered right after a top-level transaction is committed yii\db\Connection
EVENT_ROLLBACK_TRANSACTION yii\base\Event An event that is triggered right after a top-level transaction is rolled back yii\db\Connection

Property Details

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$attributes public property

PDO attributes (name => value) that should be set when calling open() to establish a DB connection. Please refer to the PHP manual for details about available attributes.

public array $attributes null
$charset public property

The charset used for database connection. The property is only used for MySQL, PostgreSQL and CUBRID databases. Defaults to null, meaning using default charset as configured by the database.

For Oracle Database, the charset must be specified in the $dsn, for example for UTF-8 by appending ;charset=UTF-8 to the DSN string.

The same applies for if you're using GBK or BIG5 charset with MySQL, then it's highly recommended to specify charset via $dsn like 'mysql:dbname=mydatabase;host=127.0.0.1;charset=GBK;'.

public string|null $charset null
$commandClass public property (available since version 2.0.7)
Deprecated since 2.0.14. Use $commandMap for precise configuration.

The class used to create new database yii\db\Command objects. If you want to extend the yii\db\Command class, you may configure this property to use your extended version of the class. Since version 2.0.14 $commandMap is used if this property is set to its default value.

See also createCommand().

public string $commandClass 'yii\db\Command'
$commandMap public property (available since version 2.0.14)

Mapping between PDO driver names and yii\db\Command classes. The keys of the array are PDO driver names while the values are either the corresponding command class names or configurations. Please refer to Yii::createObject() for details on how to specify a configuration.

This property is mainly used by createCommand() to create new database yii\db\Command objects. You normally do not need to set this property unless you want to use your own yii\db\Command class or support DBMS that is not supported by Yii.

public array $commandMap = [
    
'pgsql' => 'yii\db\Command',
    
'mysqli' => 'yii\db\Command',
    
'mysql' => 'yii\db\Command',
    
'sqlite' => 'yii\db\sqlite\Command',
    
'sqlite2' => 'yii\db\sqlite\Command',
    
'sqlsrv' => 'yii\db\Command',
    
'oci' => 'yii\db\oci\Command',
    
'mssql' => 'yii\db\Command',
    
'dblib' => 'yii\db\Command',
    
'cubrid' => 'yii\db\Command',
]
$driverName public property

Name of the DB driver.

public string $driverName null
$dsn public property

The Data Source Name, or DSN, contains the information required to connect to the database. Please refer to the PHP manual on the format of the DSN string.

For SQLite you may use a path alias for specifying the database path, e.g. sqlite:@app/data/db.sql.

See also $charset.

public string $dsn null
$emulatePrepare public property

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.

$enableLogging public property (available since version 2.0.12)

Whether to enable logging of database queries. Defaults to true. You may want to disable this option in a production environment to gain performance if you do not need the information being logged.

See also $enableProfiling.

public boolean $enableLogging true
$enableProfiling public property (available since version 2.0.12)

Whether to enable profiling of opening database connection and database queries. Defaults to true. You may want to disable this option in a production environment to gain performance if you do not need the information being logged.

See also $enableLogging.

public boolean $enableProfiling true
$enableQueryCache public property

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. Also, only the results of the queries enclosed within cache() will be cached.

See also:

public boolean $enableQueryCache true
$enableSavepoint public property

Whether to enable savepoint. Note that if the underlying DBMS does not support savepoint, setting this property to be true will have no effect.

public boolean $enableSavepoint true
$enableSchemaCache public property

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 also:

public boolean $enableSchemaCache false
$enableSlaves public property

Whether to enable read/write splitting by using $slaves to read data. Note that if $slaves is empty, read/write splitting will NOT be enabled no matter what value this property takes.

public boolean $enableSlaves true
$isActive public property

Whether the DB connection is established.

public boolean $isActive null
$isSybase public property (available since version 2.0.38)

If the database connected via pdo_dblib is SyBase.

public boolean $isSybase false
$lastInsertID public property

The row ID of the last row inserted, or the last value retrieved from the sequence object.

public string $lastInsertID null
$master public property

The currently active master connection. null is returned if there is no master available.

public yii\db\Connection $master null
$masterConfig public property

The configuration that should be merged with every master configuration listed in $masters. For example,

[
    'username' => 'master',
    'password' => 'master',
    'attributes' => [
        // use a smaller connection timeout
        PDO::ATTR_TIMEOUT => 10,
    ],
]
public array $masterConfig = []
$masterPdo public property

The PDO instance for the currently active master connection.

public PDO $masterPdo null
$masters public property

List of master connection configurations. Each configuration is used to create a master DB connection. When open() is called, one of these configurations will be chosen and used to create a DB connection which will be used by this object. Note that when this property is not empty, the connection setting (e.g. "dsn", "username") of this object will be ignored.

See also:

public array $masters = []
$password public property

The password for establishing DB connection. Defaults to null meaning no password to use.

public string|null $password null
$pdo public property

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.

See also $pdoClass.

public PDO|null $pdo null
$pdoClass public property

Custom PDO wrapper class. If not set, it will use PDO or yii\db\mssql\PDO when MSSQL is used.

See also $pdo.

public string|null $pdoClass null
$queryBuilder public property

The query builder for the current DB connection. Note that the type of this property differs in getter and setter. See getQueryBuilder() and setQueryBuilder() for details.

$queryCache public property

The cache object or the ID of the cache application component that is used for query caching.

See also $enableQueryCache.

$queryCacheDuration public property

The default 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. The value of this property will be used when cache() is called without a cache duration.

See also:

$schema public property

The schema information for the database opened by this connection.

public yii\db\Schema $schema null
$schemaCache public property

The cache object or the ID of the cache application component that is used to cache the table metadata.

See also $enableSchemaCache.

$schemaCacheDuration public property

Number of seconds that table metadata can remain valid in cache. Use 0 to indicate that the cached data will never expire.

See also $enableSchemaCache.

$schemaCacheExclude public property

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 also $enableSchemaCache.

$schemaMap public property

Mapping between PDO driver names and yii\db\Schema classes. The keys of the array are PDO driver names while the values are either the corresponding schema class names or configurations. 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 yii\db\Schema class to support DBMS that is not supported by Yii.

public array $schemaMap = [
    
'pgsql' => 'yii\db\pgsql\Schema',
    
'mysqli' => 'yii\db\mysql\Schema',
    
'mysql' => 'yii\db\mysql\Schema',
    
'sqlite' => 'yii\db\sqlite\Schema',
    
'sqlite2' => 'yii\db\sqlite\Schema',
    
'sqlsrv' => 'yii\db\mssql\Schema',
    
'oci' => 'yii\db\oci\Schema',
    
'mssql' => 'yii\db\mssql\Schema',
    
'dblib' => 'yii\db\mssql\Schema',
    
'cubrid' => 'yii\db\cubrid\Schema',
]
$serverRetryInterval public property

The retry interval in seconds for dead servers listed in $masters and $slaves. This is used together with $serverStatusCache.

$serverStatusCache public property

The cache object or the ID of the cache application component that is used to store the health status of the DB servers specified in $masters and $slaves. This is used only when read/write splitting is enabled or $masters is not empty. Set boolean false to disabled server status caching.

See also:

$serverVersion public property

Server version as a string.

public string $serverVersion null
$shuffleMasters public property (available since version 2.0.11)

Whether to shuffle $masters before getting one.

See also $masters.

public boolean $shuffleMasters true
$slave public property

The currently active slave connection. null is returned if there is no slave available and $fallbackToMaster is false.

public yii\db\Connection $slave null
$slaveConfig public property

The configuration that should be merged with every slave configuration listed in $slaves. For example,

[
    'username' => 'slave',
    'password' => 'slave',
    'attributes' => [
        // use a smaller connection timeout
        PDO::ATTR_TIMEOUT => 10,
    ],
]
public array $slaveConfig = []
$slavePdo public property

The PDO instance for the currently active slave connection. null is returned if no slave connection is available and $fallbackToMaster is false.

public PDO $slavePdo null
$slaves public property

List of slave connection configurations. Each configuration is used to create a slave DB connection. When $enableSlaves is true, one of these configurations will be chosen and used to create a DB connection for performing read queries only.

See also:

public array $slaves = []
$tablePrefix public property

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}}.

public string $tablePrefix ''
$transaction public property

The currently active transaction. Null if no active transaction.

$username public property

The username for establishing DB connection. Defaults to null meaning no username to use.

public string|null $username null

Method Details

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__call() public method

Defined in: yii\base\Component::__call()

Calls the named method which is not a class method.

This method will check if any attached behavior has the named method and will execute it if available.

Do not call this method directly as it is a PHP magic method that will be implicitly called when an unknown method is being invoked.

public mixed __call ( $name, $params )
$name string

The method name

$params array

Method parameters

return mixed

The method return value

throws yii\base\UnknownMethodException

when calling unknown method

                public function __call($name, $params)
{
    $this->ensureBehaviors();
    foreach ($this->_behaviors as $object) {
        if ($object->hasMethod($name)) {
            return call_user_func_array([$object, $name], $params);
        }
    }
    throw new UnknownMethodException('Calling unknown method: ' . get_class($this) . "::$name()");
}

            
__clone() public method

Reset the connection after cloning.

public void __clone ( )

                public function __clone()
{
    parent::__clone();
    $this->_master = false;
    $this->_slave = false;
    $this->_schema = null;
    $this->_transaction = null;
    if (strncmp($this->dsn, 'sqlite::memory:', 15) !== 0) {
        // reset PDO connection, unless its sqlite in-memory, which can only have one connection
        $this->pdo = null;
    }
}

            
__construct() public method

Defined in: yii\base\BaseObject::__construct()

Constructor.

The default implementation does two things:

  • Initializes the object with the given configuration $config.
  • Call init().

If this method is overridden in a child class, it is recommended that

  • the last parameter of the constructor is a configuration array, like $config here.
  • call the parent implementation at the end of the constructor.
public void __construct ( $config = [] )
$config array

Name-value pairs that will be used to initialize the object properties

                public function __construct($config = [])
{
    if (!empty($config)) {
        Yii::configure($this, $config);
    }
    $this->init();
}

            
__get() public method

Defined in: yii\base\Component::__get()

Returns the value of a component property.

This method will check in the following order and act accordingly:

  • a property defined by a getter: return the getter result
  • a property of a behavior: return the behavior property value

Do not call this method directly as it is a PHP magic method that will be implicitly called when executing $value = $component->property;.

See also __set().

public mixed __get ( $name )
$name string

The property name

return mixed

The property value or the value of a behavior's property

throws yii\base\UnknownPropertyException

if the property is not defined

throws yii\base\InvalidCallException

if the property is write-only.

                public function __get($name)
{
    $getter = 'get' . $name;
    if (method_exists($this, $getter)) {
        // read property, e.g. getName()
        return $this->$getter();
    }
    // behavior property
    $this->ensureBehaviors();
    foreach ($this->_behaviors as $behavior) {
        if ($behavior->canGetProperty($name)) {
            return $behavior->$name;
        }
    }
    if (method_exists($this, 'set' . $name)) {
        throw new InvalidCallException('Getting write-only property: ' . get_class($this) . '::' . $name);
    }
    throw new UnknownPropertyException('Getting unknown property: ' . get_class($this) . '::' . $name);
}

            
__isset() public method

Defined in: yii\base\Component::__isset()

Checks if a property is set, i.e. defined and not null.

This method will check in the following order and act accordingly:

  • a property defined by a setter: return whether the property is set
  • a property of a behavior: return whether the property is set
  • return false for non existing properties

Do not call this method directly as it is a PHP magic method that will be implicitly called when executing isset($component->property).

See also https://www.php.net/manual/en/function.isset.php.

public boolean __isset ( $name )
$name string

The property name or the event name

return boolean

Whether the named property is set

                public function __isset($name)
{
    $getter = 'get' . $name;
    if (method_exists($this, $getter)) {
        return $this->$getter() !== null;
    }
    // behavior property
    $this->ensureBehaviors();
    foreach ($this->_behaviors as $behavior) {
        if ($behavior->canGetProperty($name)) {
            return $behavior->$name !== null;
        }
    }
    return false;
}

            
__set() public method

Defined in: yii\base\Component::__set()

Sets the value of a component property.

This method will check in the following order and act accordingly:

  • a property defined by a setter: set the property value
  • an event in the format of "on xyz": attach the handler to the event "xyz"
  • a behavior in the format of "as xyz": attach the behavior named as "xyz"
  • a property of a behavior: set the behavior property value

Do not call this method directly as it is a PHP magic method that will be implicitly called when executing $component->property = $value;.

See also __get().

public void __set ( $name, $value )
$name string

The property name or the event name

$value mixed

The property value

throws yii\base\UnknownPropertyException

if the property is not defined

throws yii\base\InvalidCallException

if the property is read-only.

                public function __set($name, $value)
{
    $setter = 'set' . $name;
    if (method_exists($this, $setter)) {
        // set property
        $this->$setter($value);
        return;
    } elseif (strncmp($name, 'on ', 3) === 0) {
        // on event: attach event handler
        $this->on(trim(substr($name, 3)), $value);
        return;
    } elseif (strncmp($name, 'as ', 3) === 0) {
        // as behavior: attach behavior
        $name = trim(substr($name, 3));
        $this->attachBehavior($name, $value instanceof Behavior ? $value : Yii::createObject($value));
        return;
    }
    // behavior property
    $this->ensureBehaviors();
    foreach ($this->_behaviors as $behavior) {
        if ($behavior->canSetProperty($name)) {
            $behavior->$name = $value;
            return;
        }
    }
    if (method_exists($this, 'get' . $name)) {
        throw new InvalidCallException('Setting read-only property: ' . get_class($this) . '::' . $name);
    }
    throw new UnknownPropertyException('Setting unknown property: ' . get_class($this) . '::' . $name);
}

            
__sleep() public method

Close the connection before serializing.

public array __sleep ( )

                public function __sleep()
{
    $fields = (array) $this;
    unset($fields['pdo']);
    unset($fields["\000" . __CLASS__ . "\000" . '_master']);
    unset($fields["\000" . __CLASS__ . "\000" . '_slave']);
    unset($fields["\000" . __CLASS__ . "\000" . '_transaction']);
    unset($fields["\000" . __CLASS__ . "\000" . '_schema']);
    return array_keys($fields);
}

            
__unset() public method

Defined in: yii\base\Component::__unset()

Sets a component property to be null.

This method will check in the following order and act accordingly:

  • a property defined by a setter: set the property value to be null
  • a property of a behavior: set the property value to be null

Do not call this method directly as it is a PHP magic method that will be implicitly called when executing unset($component->property).

See also https://www.php.net/manual/en/function.unset.php.

public void __unset ( $name )
$name string

The property name

throws yii\base\InvalidCallException

if the property is read only.

                public function __unset($name)
{
    $setter = 'set' . $name;
    if (method_exists($this, $setter)) {
        $this->$setter(null);
        return;
    }
    // behavior property
    $this->ensureBehaviors();
    foreach ($this->_behaviors as $behavior) {
        if ($behavior->canSetProperty($name)) {
            $behavior->$name = null;
            return;
        }
    }
    throw new InvalidCallException('Unsetting an unknown or read-only property: ' . get_class($this) . '::' . $name);
}

            
attachBehavior() public method

Defined in: yii\base\Component::attachBehavior()

Attaches a behavior to this component.

This method will create the behavior object based on the given configuration. After that, the behavior object will be attached to this component by calling the yii\base\Behavior::attach() method.

See also detachBehavior().

public yii\base\Behavior attachBehavior ( $name, $behavior )
$name string

The name of the behavior.

$behavior string|array|yii\base\Behavior

The behavior configuration. This can be one of the following:

return yii\base\Behavior

The behavior object

                public function attachBehavior($name, $behavior)
{
    $this->ensureBehaviors();
    return $this->attachBehaviorInternal($name, $behavior);
}

            
attachBehaviors() public method

Defined in: yii\base\Component::attachBehaviors()

Attaches a list of behaviors to the component.

Each behavior is indexed by its name and should be a yii\base\Behavior object, a string specifying the behavior class, or an configuration array for creating the behavior.

See also attachBehavior().

public void attachBehaviors ( $behaviors )
$behaviors array

List of behaviors to be attached to the component

                public function attachBehaviors($behaviors)
{
    $this->ensureBehaviors();
    foreach ($behaviors as $name => $behavior) {
        $this->attachBehaviorInternal($name, $behavior);
    }
}

            
beginTransaction() public method

Starts a transaction.

public yii\db\Transaction beginTransaction ( $isolationLevel null )
$isolationLevel string|null

The isolation level to use for this transaction. See yii\db\Transaction::begin() for details.

return yii\db\Transaction

The transaction initiated

                public function beginTransaction($isolationLevel = null)
{
    $this->open();
    if (($transaction = $this->getTransaction()) === null) {
        $transaction = $this->_transaction = new Transaction(['db' => $this]);
    }
    $transaction->begin($isolationLevel);
    return $transaction;
}

            
behaviors() public method

Defined in: yii\base\Component::behaviors()

Returns a list of behaviors that this component should behave as.

Child classes may override this method to specify the behaviors they want to behave as.

The return value of this method should be an array of behavior objects or configurations indexed by behavior names. A behavior configuration can be either a string specifying the behavior class or an array of the following structure:

'behaviorName' => [
    'class' => 'BehaviorClass',
    'property1' => 'value1',
    'property2' => 'value2',
]

Note that a behavior class must extend from yii\base\Behavior. Behaviors can be attached using a name or anonymously. When a name is used as the array key, using this name, the behavior can later be retrieved using getBehavior() or be detached using detachBehavior(). Anonymous behaviors can not be retrieved or detached.

Behaviors declared in this method will be attached to the component automatically (on demand).

public array behaviors ( )
return array

The behavior configurations.

                public function behaviors()
{
    return [];
}

            
cache() public method

Uses query cache for the queries performed with the callable.

When query caching is enabled ($enableQueryCache is true and $queryCache refers to a valid cache), queries performed within the callable will be cached and their results will be fetched from cache if available. For example,

// The customer will be fetched from cache if available.
// If not, the query will be made against DB and cached for use next time.
$customer = $db->cache(function (Connection $db) {
    return $db->createCommand('SELECT * FROM customer WHERE id=1')->queryOne();
});

Note that query cache is only meaningful for queries that return results. For queries performed with yii\db\Command::execute(), query cache will not be used.

See also:

public mixed cache ( callable $callable, $duration null, $dependency null )
$callable callable

A PHP callable that contains DB queries which will make use of query cache. The signature of the callable is function (Connection $db).

$duration integer|null

The number of seconds that query results can remain valid in the cache. If this is not set, the value of $queryCacheDuration will be used instead. Use 0 to indicate that the cached data will never expire.

$dependency yii\caching\Dependency|null

The cache dependency associated with the cached query results.

return mixed

The return result of the callable

throws Throwable

if there is any exception during query

                public function cache(callable $callable, $duration = null, $dependency = null)
{
    $this->_queryCacheInfo[] = [$duration === null ? $this->queryCacheDuration : $duration, $dependency];
    try {
        $result = call_user_func($callable, $this);
        array_pop($this->_queryCacheInfo);
        return $result;
    } catch (\Exception $e) {
        array_pop($this->_queryCacheInfo);
        throw $e;
    } catch (\Throwable $e) {
        array_pop($this->_queryCacheInfo);
        throw $e;
    }
}

            
canGetProperty() public method

Defined in: yii\base\Component::canGetProperty()

Returns a value indicating whether a property can be read.

A property can be read if:

  • the class has a getter method associated with the specified name (in this case, property name is case-insensitive);
  • the class has a member variable with the specified name (when $checkVars is true);
  • an attached behavior has a readable property of the given name (when $checkBehaviors is true).

See also canSetProperty().

public boolean canGetProperty ( $name, $checkVars true, $checkBehaviors true )
$name string

The property name

$checkVars boolean

Whether to treat member variables as properties

$checkBehaviors boolean

Whether to treat behaviors' properties as properties of this component

return boolean

Whether the property can be read

                public function canGetProperty($name, $checkVars = true, $checkBehaviors = true)
{
    if (method_exists($this, 'get' . $name) || $checkVars && property_exists($this, $name)) {
        return true;
    } elseif ($checkBehaviors) {
        $this->ensureBehaviors();
        foreach ($this->_behaviors as $behavior) {
            if ($behavior->canGetProperty($name, $checkVars)) {
                return true;
            }
        }
    }
    return false;
}

            
canSetProperty() public method

Defined in: yii\base\Component::canSetProperty()

Returns a value indicating whether a property can be set.

A property can be written if:

  • the class has a setter method associated with the specified name (in this case, property name is case-insensitive);
  • the class has a member variable with the specified name (when $checkVars is true);
  • an attached behavior has a writable property of the given name (when $checkBehaviors is true).

See also canGetProperty().

public boolean canSetProperty ( $name, $checkVars true, $checkBehaviors true )
$name string

The property name

$checkVars boolean

Whether to treat member variables as properties

$checkBehaviors boolean

Whether to treat behaviors' properties as properties of this component

return boolean

Whether the property can be written

                public function canSetProperty($name, $checkVars = true, $checkBehaviors = true)
{
    if (method_exists($this, 'set' . $name) || $checkVars && property_exists($this, $name)) {
        return true;
    } elseif ($checkBehaviors) {
        $this->ensureBehaviors();
        foreach ($this->_behaviors as $behavior) {
            if ($behavior->canSetProperty($name, $checkVars)) {
                return true;
            }
        }
    }
    return false;
}

            
className() public static method
Deprecated since 2.0.14. On PHP >=5.5, use ::class instead.

Defined in: yii\base\BaseObject::className()

Returns the fully qualified name of this class.

public static string className ( )
return string

The fully qualified name of this class.

                public static function className()
{
    return get_called_class();
}

            
close() public method

Closes the currently active DB connection.

It does nothing if the connection is already closed.

public void close ( )

                public function close()
{
    if ($this->_master) {
        if ($this->pdo === $this->_master->pdo) {
            $this->pdo = null;
        }
        $this->_master->close();
        $this->_master = false;
    }
    if ($this->pdo !== null) {
        Yii::debug('Closing DB connection: ' . $this->dsn, __METHOD__);
        $this->pdo = null;
    }
    if ($this->_slave) {
        $this->_slave->close();
        $this->_slave = false;
    }
    $this->_schema = null;
    $this->_transaction = null;
    $this->_driverName = null;
    $this->_queryCacheInfo = [];
    $this->_quotedTableNames = null;
    $this->_quotedColumnNames = null;
}

            
createCommand() public method

Creates a command for execution.

public yii\db\Command createCommand ( $sql null, $params = [] )
$sql string|null

The SQL statement to be executed

$params array

The parameters to be bound to the SQL statement

return yii\db\Command

The DB command

                public function createCommand($sql = null, $params = [])
{
    $driver = $this->getDriverName();
    $config = ['class' => 'yii\db\Command'];
    if ($this->commandClass !== $config['class']) {
        $config['class'] = $this->commandClass;
    } elseif (isset($this->commandMap[$driver])) {
        $config = !is_array($this->commandMap[$driver]) ? ['class' => $this->commandMap[$driver]] : $this->commandMap[$driver];
    }
    $config['db'] = $this;
    $config['sql'] = $sql;
    /** @var Command $command */
    $command = Yii::createObject($config);
    return $command->bindValues($params);
}

            
createPdoInstance() protected method

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.

protected PDO createPdoInstance ( )
return PDO

The pdo instance

                protected function createPdoInstance()
{
    $pdoClass = $this->pdoClass;
    if ($pdoClass === null) {
        $driver = null;
        if ($this->_driverName !== null) {
            $driver = $this->_driverName;
        } elseif (($pos = strpos($this->dsn, ':')) !== false) {
            $driver = strtolower(substr($this->dsn, 0, $pos));
        }
        switch ($driver) {
            case 'mssql':
                $pdoClass = 'yii\db\mssql\PDO';
                break;
            case 'dblib':
                $pdoClass = 'yii\db\mssql\DBLibPDO';
                break;
            case 'sqlsrv':
                $pdoClass = 'yii\db\mssql\SqlsrvPDO';
                break;
            default:
                $pdoClass = 'PDO';
        }
    }
    $dsn = $this->dsn;
    if (strncmp('sqlite:@', $dsn, 8) === 0) {
        $dsn = 'sqlite:' . Yii::getAlias(substr($dsn, 7));
    }
    return new $pdoClass($dsn, $this->username, $this->password, $this->attributes);
}

            
detachBehavior() public method

Defined in: yii\base\Component::detachBehavior()

Detaches a behavior from the component.

The behavior's yii\base\Behavior::detach() method will be invoked.

public yii\base\Behavior|null detachBehavior ( $name )
$name string

The behavior's name.

return yii\base\Behavior|null

The detached behavior. Null if the behavior does not exist.

                public function detachBehavior($name)
{
    $this->ensureBehaviors();
    if (isset($this->_behaviors[$name])) {
        $behavior = $this->_behaviors[$name];
        unset($this->_behaviors[$name]);
        $behavior->detach();
        return $behavior;
    }
    return null;
}

            
detachBehaviors() public method

Defined in: yii\base\Component::detachBehaviors()

Detaches all behaviors from the component.

public void detachBehaviors ( )

                public function detachBehaviors()
{
    $this->ensureBehaviors();
    foreach ($this->_behaviors as $name => $behavior) {
        $this->detachBehavior($name);
    }
}

            
ensureBehaviors() public method

Defined in: yii\base\Component::ensureBehaviors()

Makes sure that the behaviors declared in behaviors() are attached to this component.

public void ensureBehaviors ( )

                public function ensureBehaviors()
{
    if ($this->_behaviors === null) {
        $this->_behaviors = [];
        foreach ($this->behaviors() as $name => $behavior) {
            $this->attachBehaviorInternal($name, $behavior);
        }
    }
}

            
getBehavior() public method

Defined in: yii\base\Component::getBehavior()

Returns the named behavior object.

public yii\base\Behavior|null getBehavior ( $name )
$name string

The behavior name

return yii\base\Behavior|null

The behavior object, or null if the behavior does not exist

                public function getBehavior($name)
{
    $this->ensureBehaviors();
    return isset($this->_behaviors[$name]) ? $this->_behaviors[$name] : null;
}

            
getBehaviors() public method

Defined in: yii\base\Component::getBehaviors()

Returns all behaviors attached to this component.

public yii\base\Behavior[] getBehaviors ( )
return yii\base\Behavior[]

List of behaviors attached to this component

                public function getBehaviors()
{
    $this->ensureBehaviors();
    return $this->_behaviors;
}

            
getDriverName() public method

Returns the name of the DB driver. Based on the the current $dsn, in case it was not set explicitly by an end user.

public string|null getDriverName ( )
return string|null

Name of the DB driver

                public function getDriverName()
{
    if ($this->_driverName === null) {
        if (($pos = strpos((string)$this->dsn, ':')) !== false) {
            $this->_driverName = strtolower(substr($this->dsn, 0, $pos));
        } else {
            $this->_driverName = strtolower($this->getSlavePdo()->getAttribute(PDO::ATTR_DRIVER_NAME));
        }
    }
    return $this->_driverName;
}

            
getIsActive() public method

Returns a value indicating whether the DB connection is established.

public boolean getIsActive ( )
return boolean

Whether the DB connection is established

                public function getIsActive()
{
    return $this->pdo !== null;
}

            
getLastInsertID() public method

Returns the ID of the last inserted row or sequence value.

See also https://www.php.net/manual/en/pdo.lastinsertid.php.

public string getLastInsertID ( $sequenceName '' )
$sequenceName string

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

                public function getLastInsertID($sequenceName = '')
{
    return $this->getSchema()->getLastInsertID($sequenceName);
}

            
getMaster() public method (available since version 2.0.11)

Returns the currently active master connection.

If this method is called for the first time, it will try to open a master connection.

public yii\db\Connection|null getMaster ( )
return yii\db\Connection|null

The currently active master connection. null is returned if there is no master available.

                public function getMaster()
{
    if ($this->_master === false) {
        $this->_master = $this->shuffleMasters
            ? $this->openFromPool($this->masters, $this->masterConfig)
            : $this->openFromPoolSequentially($this->masters, $this->masterConfig);
    }
    return $this->_master;
}

            
getMasterPdo() public method

Returns the PDO instance for the currently active master connection.

This method will open the master DB connection and then return $pdo.

public PDO getMasterPdo ( )
return PDO

The PDO instance for the currently active master connection.

                public function getMasterPdo()
{
    $this->open();
    return $this->pdo;
}

            
getQueryBuilder() public method

Returns the query builder for the current DB connection.

public yii\db\QueryBuilder getQueryBuilder ( )
return yii\db\QueryBuilder

The query builder for the current DB connection.

                public function getQueryBuilder()
{
    return $this->getSchema()->getQueryBuilder();
}

            
getSchema() public method

Returns the schema information for the database opened by this connection.

public yii\db\Schema getSchema ( )
return yii\db\Schema

The schema information for the database opened by this connection.

throws yii\base\NotSupportedException

if there is no support for the current driver type

                public function getSchema()
{
    if ($this->_schema !== null) {
        return $this->_schema;
    }
    $driver = $this->getDriverName();
    if (isset($this->schemaMap[$driver])) {
        $config = !is_array($this->schemaMap[$driver]) ? ['class' => $this->schemaMap[$driver]] : $this->schemaMap[$driver];
        $config['db'] = $this;
        $this->_schema = Yii::createObject($config);
        $this->restoreQueryBuilderConfiguration();
        return $this->_schema;
    }
    throw new NotSupportedException("Connection does not support reading schema information for '$driver' DBMS.");
}

            
getServerVersion() public method (available since version 2.0.14)

Returns a server version as a string comparable by \version_compare().

public string getServerVersion ( )
return string

Server version as a string.

                public function getServerVersion()
{
    return $this->getSchema()->getServerVersion();
}

            
getSlave() public method

Returns the currently active slave connection.

If this method is called for the first time, it will try to open a slave connection when $enableSlaves is true.

public yii\db\Connection|null getSlave ( $fallbackToMaster true )
$fallbackToMaster boolean

Whether to return a master connection in case there is no slave connection available.

return yii\db\Connection|null

The currently active slave connection. null is returned if there is no slave available and $fallbackToMaster is false.

                public function getSlave($fallbackToMaster = true)
{
    if (!$this->enableSlaves) {
        return $fallbackToMaster ? $this : null;
    }
    if ($this->_slave === false) {
        $this->_slave = $this->openFromPool($this->slaves, $this->slaveConfig);
    }
    return $this->_slave === null && $fallbackToMaster ? $this : $this->_slave;
}

            
getSlavePdo() public method

Returns the PDO instance for the currently active slave connection.

When $enableSlaves is true, one of the slaves will be used for read queries, and its PDO instance will be returned by this method.

public PDO|null getSlavePdo ( $fallbackToMaster true )
$fallbackToMaster boolean

Whether to return a master PDO in case none of the slave connections is available.

return PDO|null

The PDO instance for the currently active slave connection. null is returned if no slave connection is available and $fallbackToMaster is false.

                public function getSlavePdo($fallbackToMaster = true)
{
    $db = $this->getSlave(false);
    if ($db === null) {
        return $fallbackToMaster ? $this->getMasterPdo() : null;
    }
    return $db->pdo;
}

            
getTableSchema() public method

Obtains the schema information for the named table.

public yii\db\TableSchema|null getTableSchema ( $name, $refresh false )
$name string

Table name.

$refresh boolean

Whether to reload the table schema even if it is found in the cache.

return yii\db\TableSchema|null

Table schema information. Null if the named table does not exist.

                public function getTableSchema($name, $refresh = false)
{
    return $this->getSchema()->getTableSchema($name, $refresh);
}

            
getTransaction() public method

Returns the currently active transaction.

public yii\db\Transaction|null getTransaction ( )
return yii\db\Transaction|null

The currently active transaction. Null if no active transaction.

                public function getTransaction()
{
    return $this->_transaction && $this->_transaction->getIsActive() ? $this->_transaction : null;
}

            
hasEventHandlers() public method

Defined in: yii\base\Component::hasEventHandlers()

Returns a value indicating whether there is any handler attached to the named event.

public boolean hasEventHandlers ( $name )
$name string

The event name

return boolean

Whether there is any handler attached to the event.

                public function hasEventHandlers($name)
{
    $this->ensureBehaviors();
    if (!empty($this->_events[$name])) {
        return true;
    }
    foreach ($this->_eventWildcards as $wildcard => $handlers) {
        if (!empty($handlers) && StringHelper::matchWildcard($wildcard, $name)) {
            return true;
        }
    }
    return Event::hasHandlers($this, $name);
}

            
hasMethod() public method

Defined in: yii\base\Component::hasMethod()

Returns a value indicating whether a method is defined.

A method is defined if:

  • the class has a method with the specified name
  • an attached behavior has a method with the given name (when $checkBehaviors is true).
public boolean hasMethod ( $name, $checkBehaviors true )
$name string

The property name

$checkBehaviors boolean

Whether to treat behaviors' methods as methods of this component

return boolean

Whether the method is defined

                public function hasMethod($name, $checkBehaviors = true)
{
    if (method_exists($this, $name)) {
        return true;
    } elseif ($checkBehaviors) {
        $this->ensureBehaviors();
        foreach ($this->_behaviors as $behavior) {
            if ($behavior->hasMethod($name)) {
                return true;
            }
        }
    }
    return false;
}

            
hasProperty() public method

Defined in: yii\base\Component::hasProperty()

Returns a value indicating whether a property is defined for this component.

A property is defined if:

  • the class has a getter or setter method associated with the specified name (in this case, property name is case-insensitive);
  • the class has a member variable with the specified name (when $checkVars is true);
  • an attached behavior has a property of the given name (when $checkBehaviors is true).

See also:

public boolean hasProperty ( $name, $checkVars true, $checkBehaviors true )
$name string

The property name

$checkVars boolean

Whether to treat member variables as properties

$checkBehaviors boolean

Whether to treat behaviors' properties as properties of this component

return boolean

Whether the property is defined

                public function hasProperty($name, $checkVars = true, $checkBehaviors = true)
{
    return $this->canGetProperty($name, $checkVars, $checkBehaviors) || $this->canSetProperty($name, false, $checkBehaviors);
}

            
init() public method

Defined in: yii\base\BaseObject::init()

Initializes the object.

This method is invoked at the end of the constructor after the object is initialized with the given configuration.

public void init ( )

                public function init()
{
}

            
initConnection() protected method

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 void initConnection ( )

                protected function initConnection()
{
    $this->pdo->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
    if ($this->emulatePrepare !== null && constant('PDO::ATTR_EMULATE_PREPARES')) {
        if ($this->driverName !== 'sqlsrv') {
            $this->pdo->setAttribute(PDO::ATTR_EMULATE_PREPARES, $this->emulatePrepare);
        }
    }
    if (PHP_VERSION_ID >= 80100 && $this->getDriverName() === 'sqlite') {
        $this->pdo->setAttribute(PDO::ATTR_STRINGIFY_FETCHES, true);
    }
    if (!$this->isSybase && in_array($this->getDriverName(), ['mssql', 'dblib'], true)) {
        $this->pdo->exec('SET ANSI_NULL_DFLT_ON ON');
    }
    if ($this->charset !== null && in_array($this->getDriverName(), ['pgsql', 'mysql', 'mysqli', 'cubrid'], true)) {
        $this->pdo->exec('SET NAMES ' . $this->pdo->quote($this->charset));
    }
    $this->trigger(self::EVENT_AFTER_OPEN);
}

            
noCache() public method

Disables query cache temporarily.

Queries performed within the callable will not use query cache at all. For example,

$db->cache(function (Connection $db) {

    // ... queries that use query cache ...

    return $db->noCache(function (Connection $db) {
        // this query will not use query cache
        return $db->createCommand('SELECT * FROM customer WHERE id=1')->queryOne();
    });
});

See also:

public mixed noCache ( callable $callable )
$callable callable

A PHP callable that contains DB queries which should not use query cache. The signature of the callable is function (Connection $db).

return mixed

The return result of the callable

throws Throwable

if there is any exception during query

                public function noCache(callable $callable)
{
    $this->_queryCacheInfo[] = false;
    try {
        $result = call_user_func($callable, $this);
        array_pop($this->_queryCacheInfo);
        return $result;
    } catch (\Exception $e) {
        array_pop($this->_queryCacheInfo);
        throw $e;
    } catch (\Throwable $e) {
        array_pop($this->_queryCacheInfo);
        throw $e;
    }
}

            
off() public method

Defined in: yii\base\Component::off()

Detaches an existing event handler from this component.

This method is the opposite of on().

Note: in case wildcard pattern is passed for event name, only the handlers registered with this wildcard will be removed, while handlers registered with plain names matching this wildcard will remain.

See also on().

public boolean off ( $name, $handler null )
$name string

Event name

$handler callable|null

The event handler to be removed. If it is null, all handlers attached to the named event will be removed.

return boolean

If a handler is found and detached

                public function off($name, $handler = null)
{
    $this->ensureBehaviors();
    if (empty($this->_events[$name]) && empty($this->_eventWildcards[$name])) {
        return false;
    }
    if ($handler === null) {
        unset($this->_events[$name], $this->_eventWildcards[$name]);
        return true;
    }
    $removed = false;
    // plain event names
    if (isset($this->_events[$name])) {
        foreach ($this->_events[$name] as $i => $event) {
            if ($event[0] === $handler) {
                unset($this->_events[$name][$i]);
                $removed = true;
            }
        }
        if ($removed) {
            $this->_events[$name] = array_values($this->_events[$name]);
            return true;
        }
    }
    // wildcard event names
    if (isset($this->_eventWildcards[$name])) {
        foreach ($this->_eventWildcards[$name] as $i => $event) {
            if ($event[0] === $handler) {
                unset($this->_eventWildcards[$name][$i]);
                $removed = true;
            }
        }
        if ($removed) {
            $this->_eventWildcards[$name] = array_values($this->_eventWildcards[$name]);
            // remove empty wildcards to save future redundant regex checks:
            if (empty($this->_eventWildcards[$name])) {
                unset($this->_eventWildcards[$name]);
            }
        }
    }
    return $removed;
}

            
on() public method

Defined in: yii\base\Component::on()

Attaches an event handler to an event.

The event handler must be a valid PHP callback. The following are some examples:

function ($event) { ... }         // anonymous function
[$object, 'handleClick']          // $object->handleClick()
['Page', 'handleClick']           // Page::handleClick()
'handleClick'                     // global function handleClick()

The event handler must be defined with the following signature,

function ($event)

where $event is an yii\base\Event object which includes parameters associated with the event.

Since 2.0.14 you can specify event name as a wildcard pattern:

$component->on('event.group.*', function ($event) {
    Yii::trace($event->name . ' is triggered.');
});

See also off().

public void on ( $name, $handler, $data null, $append true )
$name string

The event name

$handler callable

The event handler

$data mixed

The data to be passed to the event handler when the event is triggered. When the event handler is invoked, this data can be accessed via yii\base\Event::$data.

$append boolean

Whether to append new event handler to the end of the existing handler list. If false, the new handler will be inserted at the beginning of the existing handler list.

                public function on($name, $handler, $data = null, $append = true)
{
    $this->ensureBehaviors();
    if (strpos($name, '*') !== false) {
        if ($append || empty($this->_eventWildcards[$name])) {
            $this->_eventWildcards[$name][] = [$handler, $data];
        } else {
            array_unshift($this->_eventWildcards[$name], [$handler, $data]);
        }
        return;
    }
    if ($append || empty($this->_events[$name])) {
        $this->_events[$name][] = [$handler, $data];
    } else {
        array_unshift($this->_events[$name], [$handler, $data]);
    }
}

            
open() public method

Establishes a DB connection.

It does nothing if a DB connection has already been established.

public void open ( )
throws yii\db\Exception

if connection fails

                public function open()
{
    if ($this->pdo !== null) {
        return;
    }
    if (!empty($this->masters)) {
        $db = $this->getMaster();
        if ($db !== null) {
            $this->pdo = $db->pdo;
            return;
        }
        throw new InvalidConfigException('None of the master DB servers is available.');
    }
    if (empty($this->dsn)) {
        throw new InvalidConfigException('Connection::dsn cannot be empty.');
    }
    $token = 'Opening DB connection: ' . $this->dsn;
    $enableProfiling = $this->enableProfiling;
    try {
        if ($this->enableLogging) {
            Yii::info($token, __METHOD__);
        }
        if ($enableProfiling) {
            Yii::beginProfile($token, __METHOD__);
        }
        $this->pdo = $this->createPdoInstance();
        $this->initConnection();
        if ($enableProfiling) {
            Yii::endProfile($token, __METHOD__);
        }
    } catch (\PDOException $e) {
        if ($enableProfiling) {
            Yii::endProfile($token, __METHOD__);
        }
        throw new Exception($e->getMessage(), $e->errorInfo, (int) $e->getCode(), $e);
    }
}

            
openFromPool() protected method

Opens the connection to a server in the pool.

This method implements load balancing and failover among the given list of the servers. Connections will be tried in random order. For details about the failover behavior, see openFromPoolSequentially().

See also openFromPoolSequentially().

protected yii\db\Connection|null openFromPool ( array $pool, array $sharedConfig )
$pool array

The list of connection configurations in the server pool

$sharedConfig array

The configuration common to those given in $pool.

return yii\db\Connection|null

The opened DB connection, or null if no server is available

throws yii\base\InvalidConfigException

if a configuration does not specify "dsn"

                protected function openFromPool(array $pool, array $sharedConfig)
{
    shuffle($pool);
    return $this->openFromPoolSequentially($pool, $sharedConfig);
}

            
openFromPoolSequentially() protected method (available since version 2.0.11)

Opens the connection to a server in the pool.

This method implements failover among the given list of servers. Connections will be tried in sequential order. The first successful connection will return.

If $serverStatusCache is configured, this method will cache information about unreachable servers and does not try to connect to these for the time configured in $serverRetryInterval. This helps to keep the application stable when some servers are unavailable. Avoiding connection attempts to unavailable servers saves time when the connection attempts fail due to timeout.

If none of the servers are available the status cache is ignored and connection attempts are made to all servers (Since version 2.0.35). This is to avoid downtime when all servers are unavailable for a short time. After a successful connection attempt the server is marked as available again.

See also:

protected yii\db\Connection|null openFromPoolSequentially ( array $pool, array $sharedConfig )
$pool array

The list of connection configurations in the server pool

$sharedConfig array

The configuration common to those given in $pool.

return yii\db\Connection|null

The opened DB connection, or null if no server is available

throws yii\base\InvalidConfigException

if a configuration does not specify "dsn"

                protected function openFromPoolSequentially(array $pool, array $sharedConfig)
{
    if (empty($pool)) {
        return null;
    }
    if (!isset($sharedConfig['class'])) {
        $sharedConfig['class'] = get_class($this);
    }
    $cache = is_string($this->serverStatusCache) ? Yii::$app->get($this->serverStatusCache, false) : $this->serverStatusCache;
    foreach ($pool as $i => $config) {
        $pool[$i] = $config = array_merge($sharedConfig, $config);
        if (empty($config['dsn'])) {
            throw new InvalidConfigException('The "dsn" option must be specified.');
        }
        $key = [__METHOD__, $config['dsn']];
        if ($cache instanceof CacheInterface && $cache->get($key)) {
            // should not try this dead server now
            continue;
        }
        /* @var $db Connection */
        $db = Yii::createObject($config);
        try {
            $db->open();
            return $db;
        } catch (\Exception $e) {
            Yii::warning("Connection ({$config['dsn']}) failed: " . $e->getMessage(), __METHOD__);
            if ($cache instanceof CacheInterface) {
                // mark this server as dead and only retry it after the specified interval
                $cache->set($key, 1, $this->serverRetryInterval);
            }
            // exclude server from retry below
            unset($pool[$i]);
        }
    }
    if ($cache instanceof CacheInterface) {
        // if server status cache is enabled and no server is available
        // ignore the cache and try to connect anyway
        // $pool now only contains servers we did not already try in the loop above
        foreach ($pool as $config) {
            /* @var $db Connection */
            $db = Yii::createObject($config);
            try {
                $db->open();
            } catch (\Exception $e) {
                Yii::warning("Connection ({$config['dsn']}) failed: " . $e->getMessage(), __METHOD__);
                continue;
            }
            // mark this server as available again after successful connection
            $cache->delete([__METHOD__, $config['dsn']]);
            return $db;
        }
    }
    return null;
}

            
quoteColumnName() public method

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.

public string quoteColumnName ( $name )
$name string

Column name

return string

The properly quoted column name

                public function quoteColumnName($name)
{
    if (isset($this->_quotedColumnNames[$name])) {
        return $this->_quotedColumnNames[$name];
    }
    return $this->_quotedColumnNames[$name] = $this->getSchema()->quoteColumnName($name);
}

            
quoteSql() public method

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.

public string quoteSql ( $sql )
$sql string

The SQL to be quoted

return string

The quoted SQL

                public function quoteSql($sql)
{
    return preg_replace_callback(
        '/(\\{\\{(%?[\w\-\. ]+%?)\\}\\}|\\[\\[([\w\-\. ]+)\\]\\])/',
        function ($matches) {
            if (isset($matches[3])) {
                return $this->quoteColumnName($matches[3]);
            }
            return str_replace('%', $this->tablePrefix, $this->quoteTableName($matches[2]));
        },
        $sql
    );
}

            
quoteTableName() public method

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.

public string quoteTableName ( $name )
$name string

Table name

return string

The properly quoted table name

                public function quoteTableName($name)
{
    if (isset($this->_quotedTableNames[$name])) {
        return $this->_quotedTableNames[$name];
    }
    return $this->_quotedTableNames[$name] = $this->getSchema()->quoteTableName($name);
}

            
quoteValue() public method

Quotes a string value for use in a query.

Note that if the parameter is not a string, it will be returned without change.

See also https://www.php.net/manual/en/pdo.quote.php.

public string quoteValue ( $value )
$value string

String to be quoted

return string

The properly quoted string

                public function quoteValue($value)
{
    return $this->getSchema()->quoteValue($value);
}

            
setDriverName() public method

Changes the current driver name.

public void setDriverName ( $driverName )
$driverName string

Name of the DB driver

                public function setDriverName($driverName)
{
    $this->_driverName = strtolower($driverName);
}

            
setQueryBuilder() public method (available since version 2.0.14)

Can be used to set yii\db\QueryBuilder configuration via Connection configuration array.

public void setQueryBuilder ( $value )
$value array

The yii\db\QueryBuilder properties to be configured.

                public function setQueryBuilder($value)
{
    Yii::configure($this->getQueryBuilder(), $value);
    $this->_queryBuilderConfigurations[] = $value;
}

            
transaction() public method

Executes callback provided in a transaction.

public mixed transaction ( callable $callback, $isolationLevel null )
$callback callable

A valid PHP callback that performs the job. Accepts connection instance as parameter.

$isolationLevel string|null

The isolation level to use for this transaction. See yii\db\Transaction::begin() for details.

return mixed

Result of callback function

throws Throwable

if there is any exception during query. In this case the transaction will be rolled back.

                public function transaction(callable $callback, $isolationLevel = null)
{
    $transaction = $this->beginTransaction($isolationLevel);
    $level = $transaction->level;
    try {
        $result = call_user_func($callback, $this);
        if ($transaction->isActive && $transaction->level === $level) {
            $transaction->commit();
        }
    } catch (\Exception $e) {
        $this->rollbackTransactionOnLevel($transaction, $level);
        throw $e;
    } catch (\Throwable $e) {
        $this->rollbackTransactionOnLevel($transaction, $level);
        throw $e;
    }
    return $result;
}

            
trigger() public method

Defined in: yii\base\Component::trigger()

Triggers an event.

This method represents the happening of an event. It invokes all attached handlers for the event including class-level handlers.

public void trigger ( $name, yii\base\Event $event null )
$name string

The event name

$event yii\base\Event|null

The event instance. If not set, a default yii\base\Event object will be created.

                public function trigger($name, Event $event = null)
{
    $this->ensureBehaviors();
    $eventHandlers = [];
    foreach ($this->_eventWildcards as $wildcard => $handlers) {
        if (StringHelper::matchWildcard($wildcard, $name)) {
            $eventHandlers[] = $handlers;
        }
    }
    if (!empty($this->_events[$name])) {
        $eventHandlers[] = $this->_events[$name];
    }
    if (!empty($eventHandlers)) {
        $eventHandlers = call_user_func_array('array_merge', $eventHandlers);
        if ($event === null) {
            $event = new Event();
        }
        if ($event->sender === null) {
            $event->sender = $this;
        }
        $event->handled = false;
        $event->name = $name;
        foreach ($eventHandlers as $handler) {
            $event->data = $handler[1];
            call_user_func($handler[0], $event);
            // stop further handling if the event is handled
            if ($event->handled) {
                return;
            }
        }
    }
    // invoke class-level attached handlers
    Event::trigger($this, $name, $event);
}

            
useMaster() public method

Executes the provided callback by using the master connection.

This method is provided so that you can temporarily force using the master connection to perform DB operations even if they are read queries. For example,

$result = $db->useMaster(function ($db) {
    return $db->createCommand('SELECT * FROM user LIMIT 1')->queryOne();
});
public mixed useMaster ( callable $callback )
$callback callable

A PHP callable to be executed by this method. Its signature is function (Connection $db). Its return value will be returned by this method.

return mixed

The return value of the callback

throws Throwable

if there is any exception thrown from the callback

                public function useMaster(callable $callback)
{
    if ($this->enableSlaves) {
        $this->enableSlaves = false;
        try {
            $result = call_user_func($callback, $this);
        } catch (\Exception $e) {
            $this->enableSlaves = true;
            throw $e;
        } catch (\Throwable $e) {
            $this->enableSlaves = true;
            throw $e;
        }
        // TODO: use "finally" keyword when miminum required PHP version is >= 5.5
        $this->enableSlaves = true;
    } else {
        $result = call_user_func($callback, $this);
    }
    return $result;
}

            

Event Details

Hide inherited properties

EVENT_AFTER_OPEN event of type yii\base\Event

An event that is triggered after a DB connection is established

EVENT_BEGIN_TRANSACTION event of type yii\base\Event

An event that is triggered right before a top-level transaction is started

EVENT_COMMIT_TRANSACTION event of type yii\base\Event

An event that is triggered right after a top-level transaction is committed

EVENT_ROLLBACK_TRANSACTION event of type yii\base\Event

An event that is triggered right after a top-level transaction is rolled back