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Class yii\caching\DbDependency

All Classes | Properties | Methods
Inheritanceyii\caching\DbDependency » yii\caching\Dependency » yii\base\BaseObject
Implementsyii\base\Configurable
Available since version2.0
Source Code https://github.com/yiisoft/yii2/blob/master/framework/caching/DbDependency.php

DbDependency represents a dependency based on the query result of a SQL statement.

If the query result changes, the dependency is considered as changed. The query is specified via the $sql property.

For more details and usage information on Cache, see the guide article on caching.

Public Properties

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Property Type Description Defined By
$data mixed The dependency data that is saved in cache and later is compared with the latest dependency data. yii\caching\Dependency
$db string The application component ID of the DB connection. yii\caching\DbDependency
$params array The parameters (name => value) to be bound to the SQL statement specified by $sql. yii\caching\DbDependency
$reusable boolean Whether this dependency is reusable or not. yii\caching\Dependency
$sql string The SQL query whose result is used to determine if the dependency has been changed. yii\caching\DbDependency

Public Methods

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Method Description Defined By
__call() Calls the named method which is not a class method. yii\base\BaseObject
__construct() Constructor. yii\base\BaseObject
__get() Returns the value of an object property. yii\base\BaseObject
__isset() Checks if a property is set, i.e. defined and not null. yii\base\BaseObject
__set() Sets value of an object property. yii\base\BaseObject
__unset() Sets an object property to null. yii\base\BaseObject
canGetProperty() Returns a value indicating whether a property can be read. yii\base\BaseObject
canSetProperty() Returns a value indicating whether a property can be set. yii\base\BaseObject
className() Returns the fully qualified name of this class. yii\base\BaseObject
evaluateDependency() Evaluates the dependency by generating and saving the data related with dependency. yii\caching\Dependency
getHasChanged() Returns a value indicating whether the dependency has changed. yii\caching\Dependency
hasMethod() Returns a value indicating whether a method is defined. yii\base\BaseObject
hasProperty() Returns a value indicating whether a property is defined. yii\base\BaseObject
init() Initializes the object. yii\base\BaseObject
isChanged() Checks whether the dependency is changed. yii\caching\Dependency
resetReusableData() Resets all cached data for reusable dependencies. yii\caching\Dependency

Protected Methods

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Method Description Defined By
generateDependencyData() Generates the data needed to determine if dependency has been changed. yii\caching\DbDependency
generateReusableHash() Generates a unique hash that can be used for retrieving reusable dependency data. yii\caching\Dependency

Property Details

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$db public property

The application component ID of the DB connection.

public string $db = 'db'
$params public property

The parameters (name => value) to be bound to the SQL statement specified by $sql.

public array $params = []
$sql public property

The SQL query whose result is used to determine if the dependency has been changed. Only the first row of the query result will be used.

public string $sql = null

Method Details

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__call() public method

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

Calls the named method which is not a class method.

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, $params)
{
    throw new UnknownMethodException('Calling unknown method: ' . get_class($this) . "::$name()");
}
__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\BaseObject::__get()

Returns the value of an object property.

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

See also __set().

public mixed __get ( $name )
$name string

The property name
return mixed

The property value
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)) {
        return $this->$getter();
    } elseif (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\BaseObject::__isset()

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

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

Note that if the property is not defined, false will be returned.

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 (not null).

 

                public function __isset($name)
{
    $getter = 'get' . $name;
    if (method_exists($this, $getter)) {
        return $this->$getter() !== null;
    }
    return false;
}
__set() public method

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

Sets value of an object property.

Do not call this method directly as it is a PHP magic method that will be implicitly called when executing $object->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)) {
        $this->$setter($value);
    } elseif (method_exists($this, 'get' . $name)) {
        throw new InvalidCallException('Setting read-only property: ' . get_class($this) . '::' . $name);
    } else {
        throw new UnknownPropertyException('Setting unknown property: ' . get_class($this) . '::' . $name);
    }
}
__unset() public method

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

Sets an object property to null.

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

Note that if the property is not defined, this method will do nothing. If the property is read-only, it will throw an exception.

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);
    } elseif (method_exists($this, 'get' . $name)) {
        throw new InvalidCallException('Unsetting read-only property: ' . get_class($this) . '::' . $name);
    }
}
canGetProperty() public method

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

Returns a value indicating whether a property can be read.

A property is readable 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);

See also canSetProperty().

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

The property name
$checkVars boolean

Whether to treat member variables as properties
return boolean

Whether the property can be read

 

                public function canGetProperty($name, $checkVars = true)
{
    return method_exists($this, 'get' . $name) || $checkVars && property_exists($this, $name);
}
canSetProperty() public method

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

Returns a value indicating whether a property can be set.

A property is writable 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);

See also canGetProperty().

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

The property name
$checkVars boolean

Whether to treat member variables as properties
return boolean

Whether the property can be written

 

                public function canSetProperty($name, $checkVars = true)
{
    return method_exists($this, 'set' . $name) || $checkVars && property_exists($this, $name);
}
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();
}
evaluateDependency() public method

Defined in: yii\caching\Dependency::evaluateDependency()

Evaluates the dependency by generating and saving the data related with dependency.

This method is invoked by cache before writing data into it.

public void evaluateDependency ( $cache )
$cache yii\caching\CacheInterface

The cache component that is currently evaluating this dependency

 

                public function evaluateDependency($cache)
{
    if ($this->reusable) {
        $hash = $this->generateReusableHash();
        if (!array_key_exists($hash, self::$_reusableData)) {
            self::$_reusableData[$hash] = $this->generateDependencyData($cache);
        }
        $this->data = self::$_reusableData[$hash];
    } else {
        $this->data = $this->generateDependencyData($cache);
    }
}
generateDependencyData() protected method

Generates the data needed to determine if dependency has been changed.

This method returns the value of the global state.

protected mixed generateDependencyData ( $cache )
$cache yii\caching\CacheInterface

The cache component that is currently evaluating this dependency
return mixed

The data needed to determine if dependency has been changed.
throws yii\base\InvalidConfigException

if $db is not a valid application component ID

 

                protected function generateDependencyData($cache)
{
    /* @var $db Connection */
    $db = Instance::ensure($this->db, Connection::className());
    if ($this->sql === null) {
        throw new InvalidConfigException('DbDependency::sql must be set.');
    }
    if ($db->enableQueryCache) {
        // temporarily disable and re-enable query caching
        $db->enableQueryCache = false;
        $result = $db->createCommand($this->sql, $this->params)->queryOne();
        $db->enableQueryCache = true;
    } else {
        $result = $db->createCommand($this->sql, $this->params)->queryOne();
    }
    return $result;
}
generateReusableHash() protected method

Defined in: yii\caching\Dependency::generateReusableHash()

Generates a unique hash that can be used for retrieving reusable dependency data.

See also $reusable.

protected string generateReusableHash ( )
return string

A unique hash value for this cache dependency.

 

                protected function generateReusableHash()
{
    $clone = clone $this;
    $clone->data = null; // https://github.com/yiisoft/yii2/issues/3052
    try {
        $serialized = serialize($clone);
    } catch (\Exception $e) {
        // unserializable properties are nulled
        foreach ($clone as $name => $value) {
            if (is_object($value) && $value instanceof \Closure) {
                $clone->{$name} = null;
            }
        }
        $serialized = serialize($clone);
    }
    return sha1($serialized);
}
getHasChanged() public method
Deprecated since version 2.0.11. Will be removed in version 2.1. Use isChanged() instead.

Defined in: yii\caching\Dependency::getHasChanged()

Returns a value indicating whether the dependency has changed.

public boolean getHasChanged ( $cache )
$cache yii\caching\CacheInterface

The cache component that is currently evaluating this dependency
return boolean

Whether the dependency has changed.

 

                public function getHasChanged($cache)
{
    return $this->isChanged($cache);
}
hasMethod() public method

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

Returns a value indicating whether a method is defined.

The default implementation is a call to php function method_exists(). You may override this method when you implemented the php magic method __call().

public boolean hasMethod ( $name )
$name string

The method name
return boolean

Whether the method is defined

 

                public function hasMethod($name)
{
    return method_exists($this, $name);
}
hasProperty() public method

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

Returns a value indicating whether a property is defined.

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);

See also:

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

The property name
$checkVars boolean

Whether to treat member variables as properties
return boolean

Whether the property is defined

 

                public function hasProperty($name, $checkVars = true)
{
    return $this->canGetProperty($name, $checkVars) || $this->canSetProperty($name, false);
}
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()
{
}
isChanged() public method (available since version 2.0.11)

Defined in: yii\caching\Dependency::isChanged()

Checks whether the dependency is changed.

public boolean isChanged ( $cache )
$cache yii\caching\CacheInterface

The cache component that is currently evaluating this dependency
return boolean

Whether the dependency has changed.

 

                public function isChanged($cache)
{
    if ($this->reusable) {
        $hash = $this->generateReusableHash();
        if (!array_key_exists($hash, self::$_reusableData)) {
            self::$_reusableData[$hash] = $this->generateDependencyData($cache);
        }
        $data = self::$_reusableData[$hash];
    } else {
        $data = $this->generateDependencyData($cache);
    }
    return $data !== $this->data;
}
resetReusableData() public static method

Defined in: yii\caching\Dependency::resetReusableData()

Resets all cached data for reusable dependencies.

public static void resetReusableData ( )

                public static function resetReusableData()
{
    self::$_reusableData = [];
}