HumHub Documentation (unofficial)

Connection extends Component
in package

Application

Connection represents a connection to a database via [PDO](https://www.php.net/manual/en/book.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.

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 [[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',
    ],
],

Constants

EVENT_AFTER_OPEN = 'afterOpen'
EVENT_BEGIN_TRANSACTION = 'beginTransaction'
EVENT_COMMIT_TRANSACTION = 'commitTransaction'
EVENT_ROLLBACK_TRANSACTION = 'rollbackTransaction'

Properties

$attributes : array<string|int, mixed>
$behaviors : array<string|int, Behavior>
$charset : string|null
$commandClass : string
$commandMap : array<string|int, mixed>
$driverName : string|null
$dsn : string
$emulatePrepare : bool|null
$enableLogging : bool
$enableProfiling : bool
$enableQueryCache : bool
$enableSavepoint : bool
$enableSchemaCache : bool
$enableSlaves : bool
$isActive : bool
$isSybase : bool
$lastInsertID : string
$master : Connection|null
$masterConfig : array<string|int, mixed>
$masterPdo : PDO
$masters : array<string|int, mixed>
$password : string|null
$pdo : PDO|null
$pdoClass : string|null
$queryBuilder : QueryBuilder
$queryCache : CacheInterface|string
$queryCacheDuration : int
$schema : Schema
$schemaCache : CacheInterface|string
$schemaCacheDuration : int
$schemaCacheExclude : array<string|int, mixed>
$schemaMap : array<string|int, mixed>
$serverRetryInterval : int
$serverStatusCache : CacheInterface|string|false
$serverVersion : string
$shuffleMasters : bool
$slave : Connection|null
$slaveConfig : array<string|int, mixed>
$slavePdo : PDO|null
$slaves : array<string|int, mixed>
$tablePrefix : string
$transaction : Transaction|null
$username : string|null
$_behaviors : array<string|int, Behavior>|null
$_driverName : string
$_events : array<string|int, mixed>
$_eventWildcards : array<string|int, mixed>
$_master : Connection|false
$_queryBuilderConfigurations : array<string|int, mixed>
$_queryCacheInfo : array<string|int, mixed>
$_quotedColumnNames : array<string|int, string>
$_quotedTableNames : array<string|int, string>
$_schema : Schema
$_slave : Connection|false
$_transaction : Transaction

Methods

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

EVENT_AFTER_OPEN


    public
        mixed
    EVENT_AFTER_OPEN
    = 'afterOpen'

EVENT_BEGIN_TRANSACTION


    public
        mixed
    EVENT_BEGIN_TRANSACTION
    = 'beginTransaction'

EVENT_COMMIT_TRANSACTION


    public
        mixed
    EVENT_COMMIT_TRANSACTION
    = 'commitTransaction'

EVENT_ROLLBACK_TRANSACTION


    public
        mixed
    EVENT_ROLLBACK_TRANSACTION
    = 'rollbackTransaction'

$attributes


    public
        array<string|int, mixed>
    $attributes

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.

$behaviors read-only


    public
        array<string|int, Behavior>
    $behaviors

List of behaviors attached to this component.

$charset


    public
        string|null
    $charset

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;'.

$commandClass


    public
        string
    $commandClass
     = 'yii\db\Command'

the class used to create new database [[Command]] objects. If you want to extend the [[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.

$commandMap


    public
        array<string|int, mixed>
    $commandMap
     = [
    'pgsql' => 'yii\db\Command',
    // PostgreSQL
    'mysqli' => 'yii\db\Command',
    // MySQL
    'mysql' => 'yii\db\Command',
    // MySQL
    'sqlite' => 'yii\db\sqlite\Command',
    // sqlite 3
    'sqlite2' => 'yii\db\sqlite\Command',
    // sqlite 2
    'sqlsrv' => 'yii\db\Command',
    // newer MSSQL driver on MS Windows hosts
    'oci' => 'yii\db\oci\Command',
    // Oracle driver
    'mssql' => 'yii\db\Command',
    // older MSSQL driver on MS Windows hosts
    'dblib' => 'yii\db\Command',
    // dblib drivers on GNU/Linux (and maybe other OSes) hosts
    'cubrid' => 'yii\db\Command',
]

mapping between PDO driver names and [[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 [[Command]] objects. You normally do not need to set this property unless you want to use your own [[Command]] class or support DBMS that is not supported by Yii.

$driverName


    public
        string|null
    $driverName

Name of the DB driver. Note that the type of this property differs in getter and setter. See [[getDriverName()]] and [[setDriverName()]] for details.

$dsn


    public
        string
    $dsn

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.

$emulatePrepare


    public
        bool|null
    $emulatePrepare

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
        bool
    $enableLogging
     = true

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.

$enableProfiling


    public
        bool
    $enableProfiling
     = true

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.

$enableQueryCache


    public
        bool
    $enableQueryCache
     = true

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.

$enableSavepoint


    public
        bool
    $enableSavepoint
     = true

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

$enableSchemaCache


    public
        bool
    $enableSchemaCache
     = false

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.

$enableSlaves


    public
        bool
    $enableSlaves
     = true

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.

$isActive read-only


    public
        bool
    $isActive

Whether the DB connection is established.

$isSybase


    public
        bool
    $isSybase
     = false

If the database connected via pdo_dblib is SyBase.

$lastInsertID read-only


    public
        string
    $lastInsertID

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

$master read-only


    public
        Connection|null
    $master

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

$masterConfig


    public
        array<string|int, mixed>
    $masterConfig
     = []

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,
    ],
]

$masterPdo read-only


    public
        PDO
    $masterPdo

The PDO instance for the currently active master connection.

$masters


    public
        array<string|int, mixed>
    $masters
     = []

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.

$password


    public
        string|null
    $password

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

$pdo


    public
        PDO|null
    $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.

$pdoClass


    public
        string|null
    $pdoClass

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

$queryBuilder


    public
        QueryBuilder
    $queryBuilder

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
        CacheInterface|string
    $queryCache
     = 'cache'

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

$queryCacheDuration


    public
        int
    $queryCacheDuration
     = 3600

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.

$schema read-only


    public
        Schema
    $schema

The schema information for the database opened by this connection.

$schemaCache


    public
        CacheInterface|string
    $schemaCache
     = 'cache'

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

$schemaCacheDuration


    public
        int
    $schemaCacheDuration
     = 3600

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

$schemaCacheExclude


    public
        array<string|int, mixed>
    $schemaCacheExclude
     = []

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.

$schemaMap


    public
        array<string|int, mixed>
    $schemaMap
     = [
    'pgsql' => 'yii\db\pgsql\Schema',
    // PostgreSQL
    'mysqli' => 'yii\db\mysql\Schema',
    // MySQL
    'mysql' => 'yii\db\mysql\Schema',
    // MySQL
    'sqlite' => 'yii\db\sqlite\Schema',
    // sqlite 3
    'sqlite2' => 'yii\db\sqlite\Schema',
    // sqlite 2
    'sqlsrv' => 'yii\db\mssql\Schema',
    // newer MSSQL driver on MS Windows hosts
    'oci' => 'yii\db\oci\Schema',
    // Oracle driver
    'mssql' => 'yii\db\mssql\Schema',
    // older MSSQL driver on MS Windows hosts
    'dblib' => 'yii\db\mssql\Schema',
    // dblib drivers on GNU/Linux (and maybe other OSes) hosts
    'cubrid' => 'yii\db\cubrid\Schema',
]

mapping between PDO driver names and [[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 [[Schema]] class to support DBMS that is not supported by Yii.

$serverRetryInterval


    public
        int
    $serverRetryInterval
     = 600

the retry interval in seconds for dead servers listed in [[masters]] and [[slaves]]. This is used together with [[serverStatusCache]].

$serverStatusCache


    public
        CacheInterface|string|false
    $serverStatusCache
     = 'cache'

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.

$serverVersion read-only


    public
        string
    $serverVersion

Server version as a string.

$shuffleMasters


    public
        bool
    $shuffleMasters
     = true

whether to shuffle [[masters]] before getting one.

$slave read-only


    public
        Connection|null
    $slave

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

$slaveConfig


    public
        array<string|int, mixed>
    $slaveConfig
     = []

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,
    ],
]

$slavePdo read-only


    public
        PDO|null
    $slavePdo

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

$slaves


    public
        array<string|int, mixed>
    $slaves
     = []

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.

$tablePrefix


    public
        string
    $tablePrefix
     = ''

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}}.

$transaction read-only


    public
        Transaction|null
    $transaction

The currently active transaction. Null if no active transaction.

$username


    public
        string|null
    $username

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

$_behaviors


    private
        array<string|int, Behavior>|null
    $_behaviors

the attached behaviors (behavior name => behavior). This is null when not initialized.

$_driverName


    private
        string
    $_driverName

driver name

$_events


    private
        array<string|int, mixed>
    $_events
     = []

the attached event handlers (event name => handlers)

$_eventWildcards


    private
        array<string|int, mixed>
    $_eventWildcards
     = []

the event handlers attached for wildcard patterns (event name wildcard => handlers)

$_master


    private
        Connection|false
    $_master
     = false

the currently active master connection

$_queryBuilderConfigurations


    private
        array<string|int, mixed>
    $_queryBuilderConfigurations
     = []

An array of [[setQueryBuilder()]] calls, holding the passed arguments. Is used to restore a QueryBuilder configuration after the connection close/open cycle.

$_queryCacheInfo


    private
        array<string|int, mixed>
    $_queryCacheInfo
     = []

query cache parameters for the [[cache()]] calls

$_quotedColumnNames


    private
        array<string|int, string>
    $_quotedColumnNames

quoted column name cache for [[quoteColumnName()]] calls

$_quotedTableNames


    private
        array<string|int, string>
    $_quotedTableNames

quoted table name cache for [[quoteTableName()]] calls

$_schema


    private
        Schema
    $_schema

the database schema

$_slave


    private
        Connection|false
    $_slave
     = false

the currently active slave connection

$_transaction


    private
        Transaction
    $_transaction

the currently active transaction

__call()

Calls the named method which is not a class method.


    public
                    __call(string $name, array<string|int, mixed> $params) : mixed

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.

Parameters

$name : string: the method name
$params : array<string|int, mixed>: method parameters

Return values

mixed —

the method return value

__clone()

Reset the connection after cloning.


    public
                    __clone() : mixed

__construct()

Constructor.


    public
                    __construct([array<string|int, mixed> $config = [] ]) : mixed

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.

Parameters

$config : array<string|int, mixed> = []: name-value pairs that will be used to initialize the object properties

__get()

Returns the value of a component property.


    public
                    __get(string $name) : mixed

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;.

Parameters

$name : string: the property name

Return values

mixed —

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

__isset()

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


    public
                    __isset(string $name) : bool

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).

Parameters

$name : string: the property name or the event name

Return values

bool —

whether the named property is set

__set()

Sets the value of a component property.


    public
                    __set(string $name, mixed $value) : mixed

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;.

Parameters

$name : string: the property name or the event name
$value : mixed: the property value

__sleep()

Close the connection before serializing.


    public
                    __sleep() : array<string|int, mixed>

Return values

array<string|int, mixed>

__unset()

Sets a component property to be null.


    public
                    __unset(string $name) : mixed

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).

Parameters

$name : string: the property name

attachBehavior()

Attaches a behavior to this component.


    public
                    attachBehavior(string $name, string|array<string|int, mixed>|Behavior $behavior) : Behavior

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 [[Behavior::attach()]] method.

Parameters

$name : string

the name of the behavior.

$behavior : string|array<string|int, mixed>|Behavior

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

a [[Behavior]] object
a string specifying the behavior class
an object configuration array that will be passed to [[Yii::createObject()]] to create the behavior object.

Return values

Behavior —

the behavior object

attachBehaviors()

Attaches a list of behaviors to the component.


    public
                    attachBehaviors(array<string|int, mixed> $behaviors) : mixed

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

Parameters

$behaviors : array<string|int, mixed>: list of behaviors to be attached to the component

beginTransaction()

Starts a transaction.


    public
                    beginTransaction([string|null $isolationLevel = null ]) : Transaction

Parameters

$isolationLevel : string|null = null: The isolation level to use for this transaction. See [[Transaction::begin()]] for details.

Return values

Transaction —

the transaction initiated

behaviors()

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


    public
                    behaviors() : array<string|int, mixed>

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 [[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).

Return values

array<string|int, mixed> —

the behavior configurations.

cache()

Uses query cache for the queries performed with the callable.


    public
                    cache(callable $callable[, int|null $duration = null ][, Dependency|null $dependency = null ]) : mixed

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 [[Command::execute()]], query cache will not be used.

Parameters

$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 : int|null = 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 : Dependency|null = null: the cache dependency associated with the cached query results.

Return values

mixed —

the return result of the callable

canGetProperty()

Returns a value indicating whether a property can be read.


    public
                    canGetProperty(string $name[, bool $checkVars = true ][, bool $checkBehaviors = true ]) : bool

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).

Parameters

$name : string: the property name
$checkVars : bool = true: whether to treat member variables as properties
$checkBehaviors : bool = true: whether to treat behaviors' properties as properties of this component

Return values

bool —

whether the property can be read

canSetProperty()

Returns a value indicating whether a property can be set.


    public
                    canSetProperty(string $name[, bool $checkVars = true ][, bool $checkBehaviors = true ]) : bool

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).

Parameters

$name : string: the property name
$checkVars : bool = true: whether to treat member variables as properties
$checkBehaviors : bool = true: whether to treat behaviors' properties as properties of this component

Return values

bool —

whether the property can be written

className()

Returns the fully qualified name of this class.


    public
            static        className() : string

Return values

string —

the fully qualified name of this class.

close()

Closes the currently active DB connection.


    public
                    close() : mixed

It does nothing if the connection is already closed.

createCommand()

Creates a command for execution.


    public
                    createCommand([string|null $sql = null ][, array<string|int, mixed> $params = [] ]) : Command

Parameters

$sql : string|null = null: the SQL statement to be executed
$params : array<string|int, mixed> = []: the parameters to be bound to the SQL statement

Return values

Command —

the DB command

detachBehavior()

Detaches a behavior from the component.


    public
                    detachBehavior(string $name) : Behavior|null

The behavior's [[Behavior::detach()]] method will be invoked.

Parameters

$name : string: the behavior's name.

Return values

Behavior|null —

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

detachBehaviors()

Detaches all behaviors from the component.


    public
                    detachBehaviors() : mixed

ensureBehaviors()

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


    public
                    ensureBehaviors() : mixed

getBehavior()

Returns the named behavior object.


    public
                    getBehavior(string $name) : Behavior|null

Parameters

$name : string: the behavior name

Return values

Behavior|null —

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

getBehaviors()

Returns all behaviors attached to this component.


    public
                    getBehaviors() : array<string|int, Behavior>

Return values

array<string|int, Behavior> —

list of behaviors attached to this 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.


    public
                    getDriverName() : string|null

Return values

string|null —

name of the DB driver

getIsActive()

Returns a value indicating whether the DB connection is established.


    public
                    getIsActive() : bool

Return values

bool —

whether the DB connection is established

getLastInsertID()

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


    public
                    getLastInsertID([string $sequenceName = '' ]) : string

Parameters

$sequenceName : string = '': name of the sequence object (required by some DBMS)

Return values

string —

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

getMaster()

Returns the currently active master connection.


    public
                    getMaster() : Connection|null

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

Return values

Connection|null —

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

getMasterPdo()

Returns the PDO instance for the currently active master connection.


    public
                    getMasterPdo() : PDO

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

Return values

PDO —

the PDO instance for the currently active master connection.

getQueryBuilder()

Returns the query builder for the current DB connection.


    public
                    getQueryBuilder() : QueryBuilder

Return values

QueryBuilder —

the query builder for the current DB connection.

getSchema()

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


    public
                    getSchema() : Schema

Return values

Schema —

the schema information for the database opened by this connection.

getServerVersion()

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


    public
                    getServerVersion() : string

Return values

string —

server version as a string.

getSlave()

Returns the currently active slave connection.


    public
                    getSlave([bool $fallbackToMaster = true ]) : Connection|null

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

Parameters

$fallbackToMaster : bool = true: whether to return a master connection in case there is no slave connection available.

Return values

Connection|null —

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

getSlavePdo()

Returns the PDO instance for the currently active slave connection.


    public
                    getSlavePdo([bool $fallbackToMaster = true ]) : PDO|null

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

Parameters

$fallbackToMaster : bool = true: whether to return a master PDO in case none of the slave connections is available.

Return values

PDO|null —

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

getTableSchema()

Obtains the schema information for the named table.


    public
                    getTableSchema(string $name[, bool $refresh = false ]) : TableSchema|null

Parameters

$name : string: table name.
$refresh : bool = false: whether to reload the table schema even if it is found in the cache.

Return values

TableSchema|null —

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

getTransaction()

Returns the currently active transaction.


    public
                    getTransaction() : Transaction|null

Return values

Transaction|null —

the currently active transaction. Null if no active transaction.

hasEventHandlers()

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


    public
                    hasEventHandlers(string $name) : bool

Parameters

$name : string: the event name

Return values

bool —

whether there is any handler attached to the event.

hasMethod()

Returns a value indicating whether a method is defined.


    public
                    hasMethod(string $name[, bool $checkBehaviors = true ]) : bool

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).

Parameters

$name : string: the property name
$checkBehaviors : bool = true: whether to treat behaviors' methods as methods of this component

Return values

bool —

whether the method is defined

hasProperty()

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


    public
                    hasProperty(string $name[, bool $checkVars = true ][, bool $checkBehaviors = true ]) : bool

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).

Parameters

$name : string: the property name
$checkVars : bool = true: whether to treat member variables as properties
$checkBehaviors : bool = true: whether to treat behaviors' properties as properties of this component

Return values

bool —

whether the property is defined

init()

Initializes the object.


    public
                    init() : mixed

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

noCache()

Disables query cache temporarily.


    public
                    noCache(callable $callable) : mixed

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();
    });
});

Parameters

$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 values

mixed —

the return result of the callable

off()

Detaches an existing event handler from this component.


    public
                    off(string $name[, callable|null $handler = null ]) : bool

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.

Parameters

$name : string: event name
$handler : callable|null = null: the event handler to be removed. If it is null, all handlers attached to the named event will be removed.

Return values

bool —

if a handler is found and detached

on()

Attaches an event handler to an event.


    public
                    on(string $name, callable $handler[, mixed $data = null ][, bool $append = true ]) : mixed

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 [[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.');
});

Parameters

$name : string: the event name
$handler : callable: the event handler
$data : mixed = null: 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 [[Event::data]].
$append : bool = true: 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.

open()

Establishes a DB connection.


    public
                    open() : mixed

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

quoteColumnName()

Quotes a column name for use in a query.


    public
                    quoteColumnName(string $name) : string

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.

Parameters

$name : string: column name

Return values

string —

the properly quoted column name

quoteSql()

Processes a SQL statement by quoting table and column names that are enclosed within double brackets.


    public
                    quoteSql(string $sql) : string

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]].

Parameters

$sql : string: the SQL to be quoted

Return values

string —

the quoted SQL

quoteTableName()

Quotes a table name for use in a query.


    public
                    quoteTableName(string $name) : string

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.

Parameters

$name : string: table name

Return values

string —

the properly quoted table name

quoteValue()

Quotes a string value for use in a query.


    public
                    quoteValue(string $value) : string

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

Parameters

$value : string: string to be quoted

Return values

string —

the properly quoted string

setDriverName()

Changes the current driver name.


    public
                    setDriverName(string $driverName) : mixed

Parameters

$driverName : string: name of the DB driver

setQueryBuilder()

Can be used to set [[QueryBuilder]] configuration via Connection configuration array.


    public
                    setQueryBuilder(array<string|int, mixed> $value) : mixed

Parameters

$value : array<string|int, mixed>: the [[QueryBuilder]] properties to be configured.

transaction()

Executes callback provided in a transaction.


    public
                    transaction(callable $callback[, string|null $isolationLevel = null ]) : mixed

Parameters

$callback : callable: a valid PHP callback that performs the job. Accepts connection instance as parameter.
$isolationLevel : string|null = null: The isolation level to use for this transaction. See [[Transaction::begin()]] for details.

Return values

mixed —

result of callback function

trigger()

Triggers an event.


    public
                    trigger(string $name[, Event|null $event = null ]) : mixed

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

Parameters

$name : string: the event name
$event : Event|null = null: the event instance. If not set, a default [[Event]] object will be created.

useMaster()

Executes the provided callback by using the master connection.


    public
                    useMaster(callable $callback) : mixed

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();
});

Parameters

$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 values

mixed —

the return value of the callback

createPdoInstance()

Creates the PDO instance.


    protected
                    createPdoInstance() : PDO

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 values

PDO —

the pdo instance

initConnection()

Initializes the DB connection.


    protected
                    initConnection() : mixed

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.

openFromPool()

Opens the connection to a server in the pool.


    protected
                    openFromPool(array<string|int, mixed> $pool, array<string|int, mixed> $sharedConfig) : Connection|null

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]].

Parameters

$pool : array<string|int, mixed>: the list of connection configurations in the server pool
$sharedConfig : array<string|int, mixed>: the configuration common to those given in $pool.

Return values

Connection|null —

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

openFromPoolSequentially()

Opens the connection to a server in the pool.


    protected
                    openFromPoolSequentially(array<string|int, mixed> $pool, array<string|int, mixed> $sharedConfig) : Connection|null

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.

Parameters

$pool : array<string|int, mixed>: the list of connection configurations in the server pool
$sharedConfig : array<string|int, mixed>: the configuration common to those given in $pool.

Return values

Connection|null —

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

attachBehaviorInternal()

Attaches a behavior to this component.


    private
                    attachBehaviorInternal(string|int $name, string|array<string|int, mixed>|Behavior $behavior) : Behavior

Parameters

$name : string|int: the name of the behavior. If this is an integer, it means the behavior is an anonymous one. Otherwise, the behavior is a named one and any existing behavior with the same name will be detached first.
$behavior : string|array<string|int, mixed>|Behavior: the behavior to be attached

Return values

Behavior —

the attached behavior.

restoreQueryBuilderConfiguration()

Restores custom QueryBuilder configuration after the connection close/open cycle


    private
                    restoreQueryBuilderConfiguration() : mixed

rollbackTransactionOnLevel()

Rolls back given [[Transaction]] object if it's still active and level match.


    private
                    rollbackTransactionOnLevel(Transaction $transaction, int $level) : mixed

In some cases rollback can fail, so this method is fail safe. Exception thrown from rollback will be caught and just logged with [[\Yii::error()]].

Parameters

$transaction : Transaction: Transaction object given from [[beginTransaction()]].
$level : int: Transaction level just after [[beginTransaction()]] call.

Connection extends Component in package Application

Tags

Table of Contents

Constants

Properties

Methods

Constants

EVENT_AFTER_OPEN

Tags

EVENT_BEGIN_TRANSACTION

Tags

EVENT_COMMIT_TRANSACTION

Tags

EVENT_ROLLBACK_TRANSACTION

Tags

Properties

$attributes

$behaviors read-only

$charset

$commandClass

Tags

$commandMap

Tags

$driverName

$dsn

Tags

$emulatePrepare

$enableLogging

Tags

$enableProfiling

Tags

$enableQueryCache

Tags

$enableSavepoint

$enableSchemaCache

Tags

$enableSlaves

$isActive read-only

$isSybase

Tags

$lastInsertID read-only

$master read-only

$masterConfig

$masterPdo read-only

$masters

Tags

$password

$pdo

Tags

$pdoClass

Tags

$queryBuilder

$queryCache

Tags

$queryCacheDuration

Tags

$schema read-only

$schemaCache

Tags

$schemaCacheDuration

Tags

$schemaCacheExclude

Tags

$schemaMap

$serverRetryInterval

$serverStatusCache

Tags

$serverVersion read-only

$shuffleMasters

Tags

$slave read-only

$slaveConfig

$slavePdo read-only

Connection extends Component
in package

Application