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

Cake\Database\Expression\TupleComparison

Namespace: Cake\Database\Expression
Location: Database/Expression/Comparison.php

Properties summary

$_isMultiple protected

boolean
Whether or not the value in this expression is a traversable
$_operator protected

string
The operator used for comparing field and value
$_type protected

string|array
The type to be used for casting the value to a database representation
$_value protected

mixed
The value to be used in the right hand side of the operation
$_valueExpressions protected

Cake\Database\ExpressionInterface[]

A cached list of ExpressionInterface objects that were found in the value for this expression.

Inherited Properties

_field

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()source public

__clone( )

Create a deep clone.

Clones the field and value if they are expression objects.

__construct()source 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()source 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

string
generated placeholder

_collectExpressions()source 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

array

_flattenValue()source 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

string

_stringExpression()source 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

array
First position containing the template and the second a placeholder

getOperator()source public

getOperator( )

Returns the operator used for comparison

Returns

string

getValue()source public

getValue( )

Returns the value used for comparison

Returns

mixed

setOperator()source public

setOperator( string $operator )

Sets the operator to use for the comparison

Parameters

string $operator: The operator to be used for the comparison.

setValue()source public

setValue( mixed $value )

Sets the value

Parameters

mixed $value: The value to compare

sql()source public

sql( Cake\Database\ValueBinder $generator )

Convert the expression into a SQL fragment.

Parameters

Cake\Database\ValueBinder $generator: Placeholder generator object

Returns

string

Implementation of

Cake\Database\ExpressionInterface::sql()

traverse()source 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

Cake\Database\ExpressionInterface::traverse()

Methods used from Cake\Database\Type\ExpressionTypeCasterTrait

_castToExpression()source 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

mixed

_requiresToExpressionCasting()source 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

array

Methods used from Cake\Database\Expression\FieldTrait

getField()source public

getField( )

Returns the field name

Returns

string|Cake\Database\ExpressionInterface

setField()source public

setField( string|Cake\Database\ExpressionInterface $field )

Sets the field name

Parameters

string|Cake\Database\ExpressionInterface $field: The field to compare with.

Properties detail

$_isMultiplesource

protected boolean

Whether or not the value in this expression is a traversable

false

$_operatorsource

protected string

The operator used for comparing field and value

$_typesource

protected string|array

The type to be used for casting the value to a database representation

$_valuesource

protected mixed

The value to be used in the right hand side of the operation

$_valueExpressionssource

protected Cake\Database\ExpressionInterface[]

A cached list of ExpressionInterface objects that were found in the value for this expression.

[]

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https://api.cakephp.org/3.8/class-Cake.Database.Expression.Comparison.html