Class Comparison
A Comparison is a type of query expression that represents an operation
involving a field an operator and a value. In its most common form the
string representation of a comparison is field = value
- Cake\Database\Expression\Comparison implements Cake\Database\ExpressionInterface, Cake\Database\Expression\FieldInterface uses Cake\Database\Type\ExpressionTypeCasterTrait , Cake\Database\Expression\FieldTrait
Direct Subclasses
Properties summary
-
$_isMultipleprotectedbooleanWhether or not the value in this expression is a traversable -
$_operatorprotectedstringThe operator used for comparing field and value -
$_typeprotectedstring|arrayThe type to be used for casting the value to a database representation -
$_valueprotectedmixedThe value to be used in the right hand side of the operation -
$_valueExpressionsprotectedA cached list of ExpressionInterface objects that were found in the value for this expression.
Inherited Properties
Method Summary
-
__clone() public
Create a deep clone. -
__construct() public
Constructor -
_bindValue() protected
Registers a value in the placeholder generator and returns the generated placeholder -
_collectExpressions() protected
Returns an array with the original $values in the first position and all ExpressionInterface objects that could be found in the second position.
-
_flattenValue() protected
Converts a traversable value into a set of placeholders generated by $generator and separated by
, -
_stringExpression() protected
Returns a template and a placeholder for the value after registering it with the placeholder $generator
-
getOperator() public
Returns the operator used for comparison -
getValue() public
Returns the value used for comparison -
setOperator() public
Sets the operator to use for the comparison -
setValue() public
Sets the value -
sql() public
Convert the expression into a SQL fragment. -
traverse() public
Iterates over each part of the expression recursively for every level of the expressions tree and executes the $visitor callable passing as first parameter the instance of the expression currently being iterated.
Method Detail
__clone() public ¶
__clone( )
Create a deep clone.
Clones the field and value if they are expression objects.
__construct() public ¶
__construct( string|Cake\Database\ExpressionInterface $field , mixed $value , string $type , string $operator )
Constructor
Parameters
-
string|
Cake\Database\ExpressionInterface$field - the field name to compare to a value
- mixed $value
- The value to be used in comparison
- string $type
- the type name used to cast the value
- string $operator
- the operator used for comparing field and value
_bindValue() protected ¶
_bindValue( mixed $value , Cake\Database\ValueBinder $generator , string $type )
Registers a value in the placeholder generator and returns the generated placeholder
Parameters
- mixed $value
- The value to bind
- Cake\Database\ValueBinder $generator
- The value binder to use
- string $type
- The type of $value
Returns
generated placeholder
_collectExpressions() protected ¶
_collectExpressions( array|Traversable $values )
Returns an array with the original $values in the first position and all ExpressionInterface objects that could be found in the second position.
Parameters
- array|Traversable $values
- The rows to insert
Returns
_flattenValue() protected ¶
_flattenValue( array|Traversable $value , Cake\Database\ValueBinder $generator , string|array|null $type = 'string' )
Converts a traversable value into a set of placeholders generated by
$generator and separated by ,
Parameters
- array|Traversable $value
- the value to flatten
- Cake\Database\ValueBinder $generator
- The value binder to use
- string|array|null $type optional 'string'
- the type to cast values to
Returns
_stringExpression() protected ¶
_stringExpression( Cake\Database\ValueBinder $generator )
Returns a template and a placeholder for the value after registering it with the placeholder $generator
Parameters
- Cake\Database\ValueBinder $generator
- The value binder to use.
Returns
First position containing the template and the second a placeholder
setOperator() public ¶
setOperator( string $operator )
Sets the operator to use for the comparison
Parameters
- string $operator
- The operator to be used for the comparison.
setValue() public ¶
setValue( mixed $value )
Sets the value
Parameters
- mixed $value
- The value to compare
sql() public ¶
sql( Cake\Database\ValueBinder $generator )
Convert the expression into a SQL fragment.
Parameters
- Cake\Database\ValueBinder $generator
- Placeholder generator object
Returns
Implementation of
traverse() public ¶
traverse( callable $callable )
Iterates over each part of the expression recursively for every level of the expressions tree and executes the $visitor callable passing as first parameter the instance of the expression currently being iterated.
Parameters
- callable $callable
- $visitor The callable to apply to all nodes.
Implementation of
Methods used from Cake\Database\Type\ExpressionTypeCasterTrait
_castToExpression() protected ¶
_castToExpression( mixed $value , string $type )
Conditionally converts the passed value to an ExpressionInterface object if the type class implements the ExpressionTypeInterface. Otherwise, returns the value unmodified.
Parameters
- mixed $value
- The value to converto to ExpressionInterface
- string $type
- The type name
Returns
_requiresToExpressionCasting() protected ¶
_requiresToExpressionCasting( array $types )
Returns an array with the types that require values to be casted to expressions, out of the list of type names passed as parameter.
Parameters
- array $types
- List of type names
Returns
Methods used from Cake\Database\Expression\FieldTrait
setField() public ¶
setField( string|Cake\Database\ExpressionInterface $field )
Sets the field name
Parameters
-
string|
Cake\Database\ExpressionInterface$field - The field to compare with.
Properties detail
$_type ¶
The type to be used for casting the value to a database representation
$_valueExpressions ¶
Cake\Database\ExpressionInterface[]
A cached list of ExpressionInterface objects that were found in the value for this expression.
[]