Public Member Functions
	__construct ($identifier=null)
	Constructor.

	setIdentifier ($identifier)
	Set identifier for comparison.

	getIdentifier ()
	Get identifier of comparison.

	setSpecification ($specification)
	Set specification string to use in forming SQL predicate.

	getSpecification ()
	Get specification string to use in forming SQL predicate.

	getExpressionData ()
	Get parts for where statement.

Protected Attributes
	$specification = '%1$s IS NULL'

	$identifier

Protected Attributes inherited from AbstractExpression
	$allowedTypes

Additional Inherited Members
Public Attributes inherited from ExpressionInterface
const	TYPE_IDENTIFIER = 'identifier'

const	TYPE_VALUE = 'value'

const	TYPE_LITERAL = 'literal'

const	TYPE_SELECT = 'select'

Protected Member Functions inherited from AbstractExpression
	normalizeArgument ($argument, $defaultType=self::TYPE_VALUE)
	Normalize Argument.

Constructor & Destructor Documentation

__construct ( $identifier = null )

Constructor.

Parameters

string $identifier

Member Function Documentation

getExpressionData ( )

Get parts for where statement.

getIdentifier ( )

Get identifier of comparison.

getSpecification ( )

Get specification string to use in forming SQL predicate.

setIdentifier ( $identifier )

Set identifier for comparison.

Parameters

string $identifier

setSpecification ( $specification )

Set specification string to use in forming SQL predicate.

Parameters

string $specification

$identifier

protected

$specification = '%1$s IS NULL'

protected