Enterprise Objects Framework Release 1.1 Copyright ã1995 by NeXT Computer, Inc.  All Rights Reserved.

EONull

Inherits From:	NSObject

Conforms To:	NSCopying

Declared In:	eoaccess/EONull.h

Class Description

An EONull object represents a NULL value on the database server. When you fetch rows with an EOAdaptorChannel or enterprise objects with an EODatabaseChannel, any attribute of that row or object with a NULL value on the server will have an EONull object as its value.

EONull generates a single unique instance for any running application. You should check whether a value is NULL by using pointer equality:

if (myValue == [EONull null]) {
    /* ... */
}

Instance Variables

 None declared in this class.

Adopted Protocols

NSCopying	- copy
- copyWithZone:

Method Types

Getting the NULL object	+ null

Class Methods

null

+ (EONull *)null

Returns the unique object representing NULL values on the database server. You shouldn't use alloc and init to create an EONull object.

Instance Methods

copy

@protocol NSCopying
- copy

Returns self. There can be only one instance of EONull in an application.

copyWithZone:

@protocol NSCopying
- copyWithZone:(NSZone *)zone

Returns self. There can be only one instance of EONull in an application.