Class yii\db\Expression
Inheritance | yii\db\Expression » yii\base\BaseObject |
---|---|
Implements | yii\base\Configurable, yii\db\ExpressionInterface |
Available since version | 2.0 |
Source Code | https://github.com/yiisoft/yii2/blob/master/framework/db/Expression.php |
Expression represents a DB expression that does not need escaping or quoting.
When an Expression object is embedded within a SQL statement or fragment, it will be replaced with the $expression property value without any DB escaping or quoting. For example,
$expression = new Expression('NOW()');
$now = (new \yii\db\Query)->select($expression)->scalar(); // SELECT NOW();
echo $now; // prints the current date
Expression objects are mainly created for passing raw SQL expressions to methods of yii\db\Query, yii\db\ActiveQuery, and related classes.
An expression can also be bound with parameters specified via $params.
Public Properties
Property | Type | Description | Defined By |
---|---|---|---|
$expression | string | The DB expression | yii\db\Expression |
$params | array | List of parameters that should be bound for this expression. | yii\db\Expression |
Public Methods
Method | Description | Defined By |
---|---|---|
__call() | Calls the named method which is not a class method. | yii\base\BaseObject |
__construct() | Constructor. | yii\db\Expression |
__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 |
__toString() | String magic method. | yii\db\Expression |
__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 |
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 |
Property Details
List of parameters that should be bound for this expression. The keys are placeholders appearing in $expression and the values are the corresponding parameter values.
Method Details
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()");
}
Constructor.
public void __construct ( $expression, $params = [], $config = [] ) | ||
$expression | string |
The DB expression |
$params | array |
Parameters |
$config | array |
Name-value pairs that will be used to initialize the object properties |
public function __construct($expression, $params = [], $config = [])
{
$this->expression = $expression;
$this->params = $params;
parent::__construct($config);
}
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) . '::' . $name);
}
Defined in: yii\base\BaseObject::__isset()
Checks if a property is set, i.e. defined and not null.
Do not call this method directly as it is a PHP magic method that
will be implicitly called when executing isset($object->property)
.
Note that if the property is not defined, false will be returned.
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;
}
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);
}
}
String magic method.
public string __toString ( ) | ||
return | string |
The DB expression. |
---|
public function __toString()
{
return $this->expression;
}
Defined in: yii\base\BaseObject::__unset()
Sets an object property to null.
Do not call this method directly as it is a PHP magic method that
will be implicitly called when executing unset($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.
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);
}
}
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);
}
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);
}
::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();
}
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);
}
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);
}
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()
{
}
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