RestKit - 到同一实体的关系映射创建无限循环

Posted 2023-03-05

【中文标题】RestKit - 到同一实体的关系映射创建无限循环

【英文标题】：RestKit - Relationship mapping to same entity creates infine loop

【发布时间】：2014-03-31 06:12:50

【问题描述】：

我需要创建一个实体与同一个实体的关系。基本上它是Meetings 实体，可能有任何ParantMeeting。

这就是我建立关系的方式。

- (RKEntityMapping *)meetingsMapping 

    RKEntityMapping *meetingsMapping = [RKEntityMapping mappingForEntityForName:@"DBMeetings" inManagedObjectStore:objectManager.managedObjectStore];
    meetingsMapping.setDefaultValueForMissingAttributes = NO;
    meetingsMapping.deletionPredicate = [NSPredicate predicateWithFormat:@"shouldBeDeleted = 1"];
    [meetingsMapping setModificationAttributeForName:@"updated_at"];
    meetingsMapping.identificationAttributes = @[@"id"];

    [meetingsMapping addAttributeMappingsFromDictionary:@
                                                          @"id": @"id",
                                                          @"title": @"title",

                                                          @"start_time": @"start_time",
                                                          @"finish_time": @"finish_time",

                                                          @"lock": @"lock",
                                                          @"location": @"location",
                                                          @"sample": @"sample",

                                                          @"deleted": @"shouldBeDeleted",

                                                          @"created_at": @"created_at",
                                                          @"updated_at": @"updated_at",
                                                          @"follow_up_id": @"follow_up_id",
                                                          @"total_topics": @"total_topics",
                                                          ];

    [meetingsMapping addRelationshipMappingWithSourceKeyPath:@"tags" mapping:[self tagsMapping]];
    [meetingsMapping addRelationshipMappingWithSourceKeyPath:@"required_participants" mapping:[self contactsMapping]];
    [meetingsMapping addRelationshipMappingWithSourceKeyPath:@"optional_participants" mapping:[self contactsMapping]];
    [meetingsMapping addRelationshipMappingWithSourceKeyPath:@"readonly_participants" mapping:[self contactsMapping]];
    [meetingsMapping addRelationshipMappingWithSourceKeyPath:@"organizer" mapping:[self contactsMapping]];
    [meetingsMapping addRelationshipMappingWithSourceKeyPath:@"parent_meeting" mapping:[self meetingsMapping]];

    return meetingsMapping;

每当我为parent_meeting添加关系映射时

[meetingsMapping addRelationshipMappingWithSourceKeyPath:@"parent_meeting" mapping:[self meetingsMapping]];

它创建了一个无限循环。是否有任何其他方式可以创建与同一实体的关系。

请帮忙。

【参考方案1】：

替换引起递归的行：

[meetingsMapping addRelationshipMappingWithSourceKeyPath:@"parent_meeting" mapping:[self meetingsMapping]];

直接引用映射本身：

[meetingsMapping addRelationshipMappingWithSourceKeyPath:@"parent_meeting" mapping:meetingsMapping];

【讨论】：

感谢您的回复，它成功了。它是否记录在某处？我找不到。

映射能够引用自身？我记得没有具体记录。

我以前做过。递归关系可以通过递归映射来实现，这似乎是合乎逻辑的......

是的，你是对的，我也认为“递归关系可以通过递归映射来实现”，但我猜不出我应该使用meetingsMapping而不是[self meetingsMapping]。 :)

通过调用 [self meetingsMapping] 您并没有创建递归映射 - 您正在创建一个永无止境的映射链（因此使用递归调用而不是递归引用）。