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Core Data Managed Object를 복제하거나 복사하려면 어떻게해야합니까?
다양한 속성과 관계 유형을 포함하는 관리 대상 개체 ( "A")가 있으며 그 관계에도 자체 속성 및 관계가 있습니다. 제가하고 싶은 것은 개체 "A"에 뿌리를 둔 전체 개체 그래프를 "복사"또는 "복제"하여 "A"와 매우 유사한 새 개체 "B"를 만드는 것입니다.
더 구체적으로 말하면 "B"(또는 그 자식)에 포함 된 관계는 "A"와 관련된 개체를 가리켜서는 안됩니다. 유사한 관계가 그대로 유지되는 완전히 새로운 개체 그래프가 있어야하며 모든 개체는 동일한 속성을 갖지만 물론 다른 ID를 가져야합니다.
이 작업을 수행하는 명백한 수동 방법이 있지만 Core Data 문서에서 완전히 명확하지 않은 더 간단한 방법을 배우고 싶었습니다.
TIA!
다음은 관리되는 개체의 "전체 복사"를 수행하기 위해 만든 클래스입니다 : 특성 및 관계. 이것은 개체 그래프의 루프를 확인하지 않습니다. (시작 지점에 대해 Jaanus에게 감사드립니다 ...)
@interface ManagedObjectCloner : NSObject {
}
+(NSManagedObject *)clone:(NSManagedObject *)source inContext:(NSManagedObjectContext *)context;
@end
@implementation ManagedObjectCloner
+(NSManagedObject *) clone:(NSManagedObject *)source inContext:(NSManagedObjectContext *)context{
NSString *entityName = [[source entity] name];
//create new object in data store
NSManagedObject *cloned = [NSEntityDescription
insertNewObjectForEntityForName:entityName
inManagedObjectContext:context];
//loop through all attributes and assign then to the clone
NSDictionary *attributes = [[NSEntityDescription
entityForName:entityName
inManagedObjectContext:context] attributesByName];
for (NSString *attr in attributes) {
[cloned setValue:[source valueForKey:attr] forKey:attr];
}
//Loop through all relationships, and clone them.
NSDictionary *relationships = [[NSEntityDescription
entityForName:entityName
inManagedObjectContext:context] relationshipsByName];
for (NSRelationshipDescription *rel in relationships){
NSString *keyName = [NSString stringWithFormat:@"%@",rel];
//get a set of all objects in the relationship
NSMutableSet *sourceSet = [source mutableSetValueForKey:keyName];
NSMutableSet *clonedSet = [cloned mutableSetValueForKey:keyName];
NSEnumerator *e = [sourceSet objectEnumerator];
NSManagedObject *relatedObject;
while ( relatedObject = [e nextObject]){
//Clone it, and add clone to set
NSManagedObject *clonedRelatedObject = [ManagedObjectCloner clone:relatedObject
inContext:context];
[clonedSet addObject:clonedRelatedObject];
}
}
return cloned;
}
@end
이 답변은 몇 가지 단점이있는 것처럼 보였지만 저를 정말 가깝게 만들었습니다.
첫째, ZS의 조언을 받아 NSManagedObject의 카테고리로 만들었습니다.
둘째, 내 개체 그래프에는 대일 관계가 포함되어 있으므로 levous의 예에서 시작했지만 대일 관계의 경우 levous의 예가 개체를 복제하지 않습니다. 이로 인해 충돌이 발생합니다 (다른 컨텍스트의 한 컨텍스트에서 NSMO 저장 시도). 나는 아래 예에서 그것을 다루었습니다.
셋째, 이미 복제 된 개체의 캐시를 제공하여 개체가 두 번 복제되어 새 개체 그래프에서 복제되는 것을 방지하고 주기도 방지합니다.
넷째, 블랙리스트 (복제 할 수없는 엔티티 유형 목록)를 추가했습니다. 최종 솔루션의 한 가지 단점을 해결하기 위해 부분적으로이 작업을 수행했습니다. 아래에서 설명하겠습니다.
참고 : 내가 이해하는 것을 CoreData 모범 사례로 사용하고 항상 역 관계를 제공 하면 복제하려는 개체와 관계가있는 모든 개체가 복제 될 수 있습니다. 역을 사용하고 있고 다른 모든 개체에 대해 알고있는 단일 루트 개체가있는 경우 전체를 복제 할 가능성이 높습니다. 이에 대한 내 해결책은 블랙리스트를 추가하고 복제하려는 개체 중 하나의 부모임을 알고있는 엔티티 유형을 전달하는 것이 었습니다. 이것은 나를 위해 일하는 것 같습니다. :)
행복한 복제!
// NSManagedObject+Clone.h
#import <CoreData/CoreData.h>
@interface NSManagedObject (Clone)
- (NSManagedObject *)cloneInContext:(NSManagedObjectContext *)context exludeEntities:(NSArray *)namesOfEntitiesToExclude;
@end
// NSManagedObject+Clone.m
#import "NSManagedObject+Clone.h"
@implementation NSManagedObject (Clone)
- (NSManagedObject *)cloneInContext:(NSManagedObjectContext *)context withCopiedCache:(NSMutableDictionary *)alreadyCopied exludeEntities:(NSArray *)namesOfEntitiesToExclude {
NSString *entityName = [[self entity] name];
if ([namesOfEntitiesToExclude containsObject:entityName]) {
return nil;
}
NSManagedObject *cloned = [alreadyCopied objectForKey:[self objectID]];
if (cloned != nil) {
return cloned;
}
//create new object in data store
cloned = [NSEntityDescription insertNewObjectForEntityForName:entityName inManagedObjectContext:context];
[alreadyCopied setObject:cloned forKey:[self objectID]];
//loop through all attributes and assign then to the clone
NSDictionary *attributes = [[NSEntityDescription entityForName:entityName inManagedObjectContext:context] attributesByName];
for (NSString *attr in attributes) {
[cloned setValue:[self valueForKey:attr] forKey:attr];
}
//Loop through all relationships, and clone them.
NSDictionary *relationships = [[NSEntityDescription entityForName:entityName inManagedObjectContext:context] relationshipsByName];
for (NSString *relName in [relationships allKeys]){
NSRelationshipDescription *rel = [relationships objectForKey:relName];
NSString *keyName = rel.name;
if ([rel isToMany]) {
//get a set of all objects in the relationship
NSMutableSet *sourceSet = [self mutableSetValueForKey:keyName];
NSMutableSet *clonedSet = [cloned mutableSetValueForKey:keyName];
NSEnumerator *e = [sourceSet objectEnumerator];
NSManagedObject *relatedObject;
while ( relatedObject = [e nextObject]){
//Clone it, and add clone to set
NSManagedObject *clonedRelatedObject = [relatedObject cloneInContext:context withCopiedCache:alreadyCopied exludeEntities:namesOfEntitiesToExclude];
[clonedSet addObject:clonedRelatedObject];
}
}else {
NSManagedObject *relatedObject = [self valueForKey:keyName];
if (relatedObject != nil) {
NSManagedObject *clonedRelatedObject = [relatedObject cloneInContext:context withCopiedCache:alreadyCopied exludeEntities:namesOfEntitiesToExclude];
[cloned setValue:clonedRelatedObject forKey:keyName];
}
}
}
return cloned;
}
- (NSManagedObject *)cloneInContext:(NSManagedObjectContext *)context exludeEntities:(NSArray *)namesOfEntitiesToExclude {
return [self cloneInContext:context withCopiedCache:[NSMutableDictionary dictionary] exludeEntities:namesOfEntitiesToExclude];
}
@end
toOne 관계를 지원하기 위해 user353759의 답변을 업데이트했습니다.
@interface ManagedObjectCloner : NSObject {
}
+(NSManagedObject *)clone:(NSManagedObject *)source inContext:(NSManagedObjectContext *)context;
@end
@implementation ManagedObjectCloner
+(NSManagedObject *) clone:(NSManagedObject *)source inContext:(NSManagedObjectContext *)context{
NSString *entityName = [[source entity] name];
//create new object in data store
NSManagedObject *cloned = [NSEntityDescription
insertNewObjectForEntityForName:entityName
inManagedObjectContext:context];
//loop through all attributes and assign then to the clone
NSDictionary *attributes = [[NSEntityDescription
entityForName:entityName
inManagedObjectContext:context] attributesByName];
for (NSString *attr in attributes) {
[cloned setValue:[source valueForKey:attr] forKey:attr];
}
//Loop through all relationships, and clone them.
NSDictionary *relationships = [[NSEntityDescription
entityForName:entityName
inManagedObjectContext:context] relationshipsByName];
for (NSString *relName in [relationships allKeys]){
NSRelationshipDescription *rel = [relationships objectForKey:relName];
NSString *keyName = [NSString stringWithFormat:@"%@",rel];
if ([rel isToMany]) {
//get a set of all objects in the relationship
NSMutableSet *sourceSet = [source mutableSetValueForKey:keyName];
NSMutableSet *clonedSet = [cloned mutableSetValueForKey:keyName];
NSEnumerator *e = [sourceSet objectEnumerator];
NSManagedObject *relatedObject;
while ( relatedObject = [e nextObject]){
//Clone it, and add clone to set
NSManagedObject *clonedRelatedObject = [ManagedObjectCloner clone:relatedObject
inContext:context];
[clonedSet addObject:clonedRelatedObject];
}
}else {
[cloned setValue:[source valueForKey:keyName] forKey:keyName];
}
}
return cloned;
}
이것은 @Derricks 답변으로, 주문 여부를 확인하기 위해 관계를 조사하여 새로운 iOS 6.0 주문 대 다 관계를 지원하도록 수정되었습니다. 거기에있는 동안 동일한 NSManagedObjectContext 내에서 일반적인 복제 사례에 대해 더 간단한 -clone 메서드를 추가했습니다.
//
// NSManagedObject+Clone.h
// Tone Poet
//
// Created by Mason Kramer on 5/31/13.
// Copyright (c) 2013 Mason Kramer. The contents of this file are available for use by anyone, for any purpose whatsoever.
//
#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>
@interface NSManagedObject (Clone) {
}
-(NSManagedObject *)cloneInContext:(NSManagedObjectContext *)context withCopiedCache:(NSMutableDictionary *)alreadyCopied exludeEntities:(NSArray *)namesOfEntitiesToExclude;
-(NSManagedObject *)cloneInContext:(NSManagedObjectContext *)context exludeEntities:(NSArray *)namesOfEntitiesToExclude;
-(NSManagedObject *) clone;
@end
//
// NSManagedObject+Clone.m
// Tone Poet
//
// Created by Mason Kramer on 5/31/13.
// Copyright (c) 2013 Mason Kramer. The contents of this file are available for use by anyone, for any purpose whatsoever.
//
#import "NSManagedObject+Clone.h"
@implementation NSManagedObject (Clone)
-(NSManagedObject *) clone {
return [self cloneInContext:[self managedObjectContext] exludeEntities:@[]];
}
- (NSManagedObject *)cloneInContext:(NSManagedObjectContext *)context withCopiedCache:(NSMutableDictionary *)alreadyCopied exludeEntities:(NSArray *)namesOfEntitiesToExclude {
NSString *entityName = [[self entity] name];
if ([namesOfEntitiesToExclude containsObject:entityName]) {
return nil;
}
NSManagedObject *cloned = [alreadyCopied objectForKey:[self objectID]];
if (cloned != nil) {
return cloned;
}
//create new object in data store
cloned = [NSEntityDescription insertNewObjectForEntityForName:entityName inManagedObjectContext:context];
[alreadyCopied setObject:cloned forKey:[self objectID]];
//loop through all attributes and assign then to the clone
NSDictionary *attributes = [[NSEntityDescription entityForName:entityName inManagedObjectContext:context] attributesByName];
for (NSString *attr in attributes) {
[cloned setValue:[self valueForKey:attr] forKey:attr];
}
//Loop through all relationships, and clone them.
NSDictionary *relationships = [[NSEntityDescription entityForName:entityName inManagedObjectContext:context] relationshipsByName];
for (NSString *relName in [relationships allKeys]){
NSRelationshipDescription *rel = [relationships objectForKey:relName];
NSString *keyName = rel.name;
if ([rel isToMany]) {
if ([rel isOrdered]) {
NSMutableOrderedSet *sourceSet = [self mutableOrderedSetValueForKey:keyName];
NSMutableOrderedSet *clonedSet = [cloned mutableOrderedSetValueForKey:keyName];
NSEnumerator *e = [sourceSet objectEnumerator];
NSManagedObject *relatedObject;
while ( relatedObject = [e nextObject]){
//Clone it, and add clone to set
NSManagedObject *clonedRelatedObject = [relatedObject cloneInContext:context withCopiedCache:alreadyCopied exludeEntities:namesOfEntitiesToExclude];
[clonedSet addObject:clonedRelatedObject];
[clonedSet addObject:clonedRelatedObject];
}
}
else {
NSMutableSet *sourceSet = [self mutableSetValueForKey:keyName];
NSMutableSet *clonedSet = [cloned mutableSetValueForKey:keyName];
NSEnumerator *e = [sourceSet objectEnumerator];
NSManagedObject *relatedObject;
while ( relatedObject = [e nextObject]){
//Clone it, and add clone to set
NSManagedObject *clonedRelatedObject = [relatedObject cloneInContext:context withCopiedCache:alreadyCopied exludeEntities:namesOfEntitiesToExclude];
[clonedSet addObject:clonedRelatedObject];
}
}
}
else {
NSManagedObject *relatedObject = [self valueForKey:keyName];
if (relatedObject != nil) {
NSManagedObject *clonedRelatedObject = [relatedObject cloneInContext:context withCopiedCache:alreadyCopied exludeEntities:namesOfEntitiesToExclude];
[cloned setValue:clonedRelatedObject forKey:keyName];
}
}
}
return cloned;
}
-(NSManagedObject *)cloneInContext:(NSManagedObjectContext *)context exludeEntities:(NSArray *)namesOfEntitiesToExclude {
return [self cloneInContext:context withCopiedCache:[NSMutableDictionary dictionary] exludeEntities:namesOfEntitiesToExclude];
}
@end
현재 답변에서 몇 가지 버그를 발견했습니다. 첫째, 무언가가 반복되는 동안 to-Many 관련 객체 세트를 변경하는 것 같습니다. 둘째, API 내에서 무언가 변경되었는지 확실하지 않지만 NSRelationshipDescription의 문자열 표현을 키로 사용하면 관련 객체를 잡을 때 예외가 발생했습니다.
나는 약간의 조정을하고, 기본적인 테스트를했고, 작동하는 것 같다. 누구든지 더 조사하고 싶다면 좋을 것입니다!
@implementation NSManagedObjectContext (DeepCopy)
-(NSManagedObject *) clone:(NSManagedObject *)source{
NSString *entityName = [[source entity] name];
//create new object in data store
NSManagedObject *cloned = [NSEntityDescription
insertNewObjectForEntityForName:entityName
inManagedObjectContext:self];
//loop through all attributes and assign then to the clone
NSDictionary *attributes = [[NSEntityDescription
entityForName:entityName
inManagedObjectContext:self] attributesByName];
for (NSString *attr in attributes) {
[cloned setValue:[source valueForKey:attr] forKey:attr];
}
//Loop through all relationships, and clone them.
NSDictionary *relationships = [[NSEntityDescription
entityForName:entityName
inManagedObjectContext:self] relationshipsByName];
for (NSString *relName in [relationships allKeys]){
NSRelationshipDescription *rel = [relationships objectForKey:relName];
if ([rel isToMany]) {
//get a set of all objects in the relationship
NSArray *sourceArray = [[source mutableSetValueForKey:relName] allObjects];
NSMutableSet *clonedSet = [cloned mutableSetValueForKey:relName];
for(NSManagedObject *relatedObject in sourceArray) {
NSManagedObject *clonedRelatedObject = [self clone:relatedObject];
[clonedSet addObject:clonedRelatedObject];
}
} else {
[cloned setValue:[source valueForKey:relName] forKey:relName];
}
}
return cloned;
}
@end
iOS 5.0 및 Mac OS X 10.7에서 사용할 수있는 정렬 된 관계 를 지원하기 위해 완벽하게 작동하는 Derrick의 답변 을 수정 했습니다 .
//
// NSManagedObject+Clone.h
//
#import <CoreData/CoreData.h>
#ifndef CD_CUSTOM_DEBUG_LOG
#define CD_CUSTOM_DEBUG_LOG NSLog
#endif
@interface NSManagedObject (Clone)
- (NSManagedObject *)cloneInContext:(NSManagedObjectContext *)context
excludeEntities:(NSArray *)namesOfEntitiesToExclude;
@end
//
// NSManagedObject+Clone.m
//
#import "NSManagedObject+Clone.h"
@interface NSManagedObject (ClonePrivate)
- (NSManagedObject *)cloneInContext:(NSManagedObjectContext *)context
withCopiedCache:(NSMutableDictionary **)alreadyCopied
excludeEntities:(NSArray *)namesOfEntitiesToExclude;
@end
@implementation NSManagedObject (Clone)
- (NSManagedObject *)cloneInContext:(NSManagedObjectContext *)context
withCopiedCache:(NSMutableDictionary **)alreadyCopied
excludeEntities:(NSArray *)namesOfEntitiesToExclude {
if (!context) {
CD_CUSTOM_DEBUG_LOG(@"%@:%@ Try to clone NSManagedObject in the 'nil' context.",
THIS_CLASS,
THIS_METHOD);
return nil;
}
NSString *entityName = [[self entity] name];
if ([namesOfEntitiesToExclude containsObject:entityName]) {
return nil;
}
NSManagedObject *cloned = nil;
if (alreadyCopied != NULL) {
cloned = [*alreadyCopied objectForKey:[self objectID]];
if (cloned) {
return cloned;
}
// Create new object in data store
cloned = [NSEntityDescription insertNewObjectForEntityForName:entityName
inManagedObjectContext:context];
[*alreadyCopied setObject:cloned forKey:[self objectID]];
} else {
CD_CUSTOM_DEBUG_LOG(@"%@:%@ NULL pointer was passed in 'alreadyCopied' argument.",
THIS_CLASS,
THIS_METHOD);
}
// Loop through all attributes and assign then to the clone
NSDictionary *attributes = [[NSEntityDescription entityForName:entityName
inManagedObjectContext:context] attributesByName];
for (NSString *attr in attributes) {
[cloned setValue:[self valueForKey:attr] forKey:attr];
}
// Loop through all relationships, and clone them.
NSDictionary *relationships = [[NSEntityDescription entityForName:entityName
inManagedObjectContext:context] relationshipsByName];
NSArray *relationshipKeys = [relationships allKeys];
for (NSString *relName in relationshipKeys) {
NSRelationshipDescription *rel = [relationships objectForKey:relName];
NSString *keyName = [rel name];
if ([rel isToMany]) {
if ([rel isOrdered]) {
// Get a set of all objects in the relationship
NSMutableOrderedSet *sourceSet = [self mutableOrderedSetValueForKey:keyName];
NSMutableOrderedSet *clonedSet = [cloned mutableOrderedSetValueForKey:keyName];
for (id relatedObject in sourceSet) {
//Clone it, and add clone to set
NSManagedObject *clonedRelatedObject = [relatedObject cloneInContext:context
withCopiedCache:alreadyCopied
excludeEntities:namesOfEntitiesToExclude];
if (clonedRelatedObject) {
[clonedSet addObject:clonedRelatedObject];
}
}
} else {
// Get a set of all objects in the relationship
NSMutableSet *sourceSet = [self mutableSetValueForKey:keyName];
NSMutableSet *clonedSet = [cloned mutableSetValueForKey:keyName];
for (id relatedObject in sourceSet) {
//Clone it, and add clone to set
NSManagedObject *clonedRelatedObject = [relatedObject cloneInContext:context
withCopiedCache:alreadyCopied
excludeEntities:namesOfEntitiesToExclude];
if (clonedRelatedObject) {
[clonedSet addObject:clonedRelatedObject];
}
}
}
} else {
NSManagedObject *relatedObject = [self valueForKey:keyName];
if (relatedObject) {
NSManagedObject *clonedRelatedObject = [relatedObject cloneInContext:context
withCopiedCache:alreadyCopied
excludeEntities:namesOfEntitiesToExclude];
[cloned setValue:clonedRelatedObject forKey:keyName];
}
}
}
return cloned;
}
- (NSManagedObject *)cloneInContext:(NSManagedObjectContext *)context
excludeEntities:(NSArray *)namesOfEntitiesToExclude {
NSMutableDictionary* mutableDictionary = [NSMutableDictionary dictionary];
return [self cloneInContext:context
withCopiedCache:&mutableDictionary
excludeEntities:namesOfEntitiesToExclude];
}
@end
@derrick이 원래 답변에서 인정한 대량 복사 문제를 해결해야했습니다. MasonK 버전에서 수정했습니다. 이것은 이전 버전에 있었던 우아함이 많지 않습니다. 하지만 내 응용 프로그램에서 주요 문제 (유사한 항목의 의도하지 않은 중복)를 해결하는 것으로 보입니다.
//
// NSManagedObject+Clone.h
#import <Foundation/Foundation.h>
#import <CoreData/CoreData.h>
@interface NSManagedObject (Clone) {
}
-(NSManagedObject *)cloneInContext:(NSManagedObjectContext *)context withCopiedCache:(NSMutableDictionary *)alreadyCopied exludeEntities:(NSMutableArray *)namesOfEntitiesToExclude isFirstPass:(BOOL)firstPass;
-(NSManagedObject *)cloneInContext:(NSManagedObjectContext *)context exludeEntities:(NSMutableArray *)namesOfEntitiesToExclude;
-(NSManagedObject *) clone;
@end
//
// NSManagedObject+Clone.m
//
#import "NSManagedObject+Clone.h"
@implementation NSManagedObject (Clone)
-(NSManagedObject *) clone {
NSMutableArray *emptyArray = [NSMutableArray arrayWithCapacity:1];
return [self cloneInContext:[self managedObjectContext] exludeEntities:emptyArray];
}
- (NSManagedObject *)cloneInContext:(NSManagedObjectContext *)context withCopiedCache:(NSMutableDictionary *)alreadyCopied exludeEntities:(NSMutableArray *)namesOfEntitiesToExclude
isFirstPass:(BOOL)firstPass
{
NSString *entityName = [[self entity] name];
if ([namesOfEntitiesToExclude containsObject:entityName]) {
return nil;
}
NSManagedObject *cloned = [alreadyCopied objectForKey:[self objectID]];
if (cloned != nil) {
return cloned;
}
//create new object in data store
cloned = [NSEntityDescription insertNewObjectForEntityForName:entityName inManagedObjectContext:context];
[alreadyCopied setObject:cloned forKey:[self objectID]];
//loop through all attributes and assign then to the clone
NSDictionary *attributes = [[NSEntityDescription entityForName:entityName inManagedObjectContext:context] attributesByName];
for (NSString *attr in attributes) {
[cloned setValue:[self valueForKey:attr] forKey:attr];
}
//Inverse relationships can cause all of the entities under one area to get duplicated
//This is the reason for "isFirstPass" and "excludeEntities"
if (firstPass == TRUE) {
[namesOfEntitiesToExclude addObject:entityName];
firstPass=FALSE;
}
//Loop through all relationships, and clone them.
NSDictionary *relationships = [[NSEntityDescription entityForName:entityName inManagedObjectContext:context] relationshipsByName];
for (NSString *relName in [relationships allKeys]){
NSRelationshipDescription *rel = [relationships objectForKey:relName];
NSString *keyName = rel.name;
if ([rel isToMany]) {
if ([rel isOrdered]) {
NSMutableOrderedSet *sourceSet = [self mutableOrderedSetValueForKey:keyName];
NSMutableOrderedSet *clonedSet = [cloned mutableOrderedSetValueForKey:keyName];
NSEnumerator *e = [sourceSet objectEnumerator];
NSManagedObject *relatedObject;
while ( relatedObject = [e nextObject]){
//Clone it, and add clone to set
NSManagedObject *clonedRelatedObject = [relatedObject cloneInContext:context withCopiedCache:alreadyCopied exludeEntities:namesOfEntitiesToExclude
isFirstPass:firstPass];
if (clonedRelatedObject != nil) {
[clonedSet addObject:clonedRelatedObject];
[clonedSet addObject:clonedRelatedObject];
}
}
}
else {
NSMutableSet *sourceSet = [self mutableSetValueForKey:keyName];
NSMutableSet *clonedSet = [cloned mutableSetValueForKey:keyName];
NSEnumerator *e = [sourceSet objectEnumerator];
NSManagedObject *relatedObject;
while ( relatedObject = [e nextObject]){
//Clone it, and add clone to set
NSManagedObject *clonedRelatedObject = [relatedObject cloneInContext:context withCopiedCache:alreadyCopied exludeEntities:namesOfEntitiesToExclude
isFirstPass:firstPass];
if (clonedRelatedObject != nil) {
[clonedSet addObject:clonedRelatedObject];
}
}
}
}
else {
NSManagedObject *relatedObject = [self valueForKey:keyName];
if (relatedObject != nil) {
NSManagedObject *clonedRelatedObject = [relatedObject cloneInContext:context withCopiedCache:alreadyCopied exludeEntities:namesOfEntitiesToExclude
isFirstPass:firstPass];
if (clonedRelatedObject != nil) {
[cloned setValue:clonedRelatedObject forKey:keyName];
}
}
}
}
return cloned;
}
-(NSManagedObject *)cloneInContext:(NSManagedObjectContext *)context exludeEntities:(NSMutableArray *)namesOfEntitiesToExclude {
return [self cloneInContext:context withCopiedCache:[NSMutableDictionary dictionary] exludeEntities:namesOfEntitiesToExclude isFirstPass:TRUE];
}
@end
당신이 요구하는 것을 "딥 카피"라고합니다. 그것이 될 수 있기 때문에 매우 (객체 그래프에서 루프를 고려) 제대로하기 (무제한의 메모리 사용량 등) 비용이 매우 어려운, 코어 데이터는 당신을 위해이 기능을 제공하지 않습니다.
그러나 종종 필요를 피하는 아키텍처가 있습니다. 전체 개체 그래프의 복사본을 만드는 대신 개체 그래프를 복사 한 다음 원본 그래프 만 참조하는 경우의 차이점 (또는 미래의 차이점)을 캡슐화하는 새 항목을 만들 수 있습니다. 즉, 새 "customizer"엔터티를 인스턴스화하고 전체 개체 그래프를 복사하지 마십시오. 예를 들어, 연립 주택 세트를 고려하십시오. 각각의 프레임과기구는 동일하지만 소유자는 페인트와 가구를 사용자 지정할 수 있습니다. 각 소유자에 대한 전체 주택 그래프를 자세히 복사하는 대신 각 소유자에 대해 소유자 및 주택 모델을 참조하는 "그림 및 가구"엔티티를 사용하십시오.
이 같은? (미확인) 이것은 언급 한 "수동 방법"이지만 모델 변경과 자동으로 동기화되므로 모든 속성 이름을 수동으로 입력 할 필요가 없습니다.
스위프트 3 :
extension NSManagedObject {
func shallowCopy() -> NSManagedObject? {
guard let context = managedObjectContext, let entityName = entity.name else { return nil }
let copy = NSEntityDescription.insertNewObject(forEntityName: entityName, into: context)
let attributes = entity.attributesByName
for (attrKey, _) in attributes {
copy.setValue(value(forKey: attrKey), forKey: attrKey)
}
return copy
}
}
목표 -C :
@interface MyObject (Clone)
- (MyObject *)clone;
@end
@implementation MyObject (Clone)
- (MyObject *)clone{
MyObject *cloned = [NSEntityDescription
insertNewObjectForEntityForName:@"MyObject"
inManagedObjectContext:moc];
NSDictionary *attributes = [[NSEntityDescription
entityForName:@"MyObject"
inManagedObjectContext:moc] attributesByName];
for (NSString *attr in attributes) {
[cloned setValue:[self valueForKey:attr] forKey:attr];
}
return cloned;
}
@end
그러면 모든 속성이있는 복제본이 반환되고 관계는 복사되지 않습니다.
여기에 내 신속한 3 접근 방식이 있습니다.
func shallowCopy(copyRelations: Bool) -> NSManagedObject? {
guard let context = managedObjectContext, let entityName = entity.name else { return nil }
let copy = NSEntityDescription.insertNewObject(forEntityName: entityName, into: context)
let attributes = entity.attributesByName
for (attrKey, _) in attributes {
copy.setValue(value(forKey: attrKey), forKey: attrKey)
}
if copyRelations {
let relations = entity.relationshipsByName
for (relKey, relValue) in relations {
if relValue.isToMany {
let sourceSet = mutableSetValue(forKey: relKey)
let clonedSet = copy.mutableSetValue(forKey: relKey)
let enumerator = sourceSet.objectEnumerator()
while let relatedObject = enumerator.nextObject() {
let clonedRelatedObject = (relatedObject as! NSManagedObject).shallowCopy(copyRelations: false)
clonedSet.add(clonedRelatedObject!)
}
} else {
copy.setValue(value(forKey: relKey), forKey: relKey)
}
}
}
return copy
}
이를 "딥 카피"라고합니다. 놀랍도록 비쌀 수 있기 때문에 많은 언어 / 라이브러리에서 즉시 지원하지 않으며 직접 롤링해야합니다. 코코아는 불행히도 그중 하나입니다.
또한:
[clone setValuesForKeysWithDictionary:[item dictionaryWithValuesForKeys:[properties allKeys]]];
[clone setValuesForKeysWithDictionary:[item dictionaryWithValuesForKeys:[attributes allKeys]]];
관계 계층의 엔터티 만 관련 시키려면 Dmitry 솔루션에 다음 코드 만 추가하면됩니다.
이 사이
NSString *entityName = [[self entity] name];
여기 if ([namesOfEntitiesToExclude containsObject : entityName]) {
NSMutableArray *arrayToOnlyRelate = [NSMutableArray arrayWithObjects:@"ENTITY 1",@"ENTITY 2",@"ENTITY 3", nil];
if ([arrayToOnlyRelate containsObject:entityName]) {
return self;
}
My take on this is at https://gist.github.com/jpmhouston/7958fceae9216f69178d4719a3492577
passes
rel.inverseRelationship.nameinto the recursive method to omit visiting the inverse relationships rather than maintaining a set ofalreadyCopiedobjectsshallow or deep copies
accepts keypaths of relationships to not clone, but to either omit, or to simply copy if the inverse is a to-many relationship
workaround for ordered,to-many relationships ending up in backwards order - simply iterate over the source entities backwards :) i'm not sure if this a good idea or if it even works all the time
Feedback & comments welcome, especially if someone can elaborate on Benjohn's comment on mis-ordering above "The work around for this is to build the complete ordered set and then assign using the primitive KVO variant." and can improve my ordered,to-many workaround.
Also, I'm using MagicalRecord and so my code assumes that, including providing easy methods that use its default context.
Swift 4.0 version
import UIKit
import CoreData
class ManagedObjectCloner: NSObject {
static func cloneObject(source :NSManagedObject, context :NSManagedObjectContext) -> NSManagedObject{
let entityName = source.entity.name
let cloned = NSEntityDescription.insertNewObject(forEntityName: entityName!, into: context)
let attributes = NSEntityDescription.entity(forEntityName: entityName!, in: context)?.attributesByName
for (key,_) in attributes! {
cloned.setValue(source.value(forKey: key), forKey: key)
}
let relationships = NSEntityDescription.entity(forEntityName: entityName!, in: context)?.relationshipsByName
for (key,_) in relationships! {
let sourceSet = source.mutableSetValue(forKey: key)
let clonedSet = cloned.mutableSetValue(forKey: key)
let e = sourceSet.objectEnumerator()
var relatedObj = e.nextObject() as? NSManagedObject
while ((relatedObj) != nil) {
let clonedRelatedObject = ManagedObjectCloner.cloneObject(source: relatedObj!, context: context)
clonedSet.add(clonedRelatedObject)
relatedObj = e.nextObject() as? NSManagedObject
}
}
return cloned
}
}
ReferenceURL : https://stackoverflow.com/questions/2730832/how-can-i-duplicate-or-copy-a-core-data-managed-object
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