我正在努力删除领域对象及其RLMArray子(和子子)对象!
下图显示了当前的域结构(Realm-Browser的屏幕截图):
如您所见,目前创建了三个RLMTopoResult对象,每个对象都有86个RLMCriteria作为children-Array. (不可见的是,每个RLMCriteria都有自己的RLMStatistics-Array – 这就是RLMCtatistics-对象与RLMCriteria-objects一样多的原因).
现在,我们的想法是删除一个RLMTopoResult(带有根据TopoNrRLM过滤的预测器)!
我应用以下代码:
- (void) removeObjects_at_TopoNr_from_LocationRLM :(NSUInteger)TopoNr :(NSString *)folderName :(NSString *)fileName { RLMRealm *realm = [RLMRealm realmWithPath:[self get_TopoResultRLM_FilePath :folderName :fileName]]; RLMResults *resultTopoResult = [RLMTopoResult allObjectsInRealm:realm]; NSPredicate *predicate = [NSPredicate predicateWithFormat:@"TopoNrRLM == %d",TopoNr]; RLMResults *resultsTopoNr = [resultTopoResult objectsWithPredicate:predicate]; if ([resultsTopoNr count] > 0) { if (TopoNr <= (int)[resultsTopoNr count]) { [realm beginWriteTransaction]; [realm deleteObject:[resultsTopoNr firstObject]]; [realm commitWriteTransaction]; } else { NSLog(@"Fail...trying to remove TopoResult-object with TopoNr bigger to object-count"); } } else { NSLog(@"Fail...trying to remove TopoResult-object in empty Realm"); } }
使用TopoNr = 2运行上述方法删除(如预期)RLMTopoResult Nr2(参见下面的结果图) – >但是,不幸的是,它没有删除它的Array-Children(和子孙)!在删除RLMTopoResult-Nr2后,仍然存在3×86 = 258 RLMCriteria(以及258 RLMStatistics).但预计会是2×86 = 172 !!!!
我该怎么做才能自动删除附加到相应RLMTopoResult的86个RLMCriteria(及其86个RLMStatistics)子节点???
任何帮助赞赏!
下图显示删除TopoResult Nr2后的结果(带上面的代码):
(预计会有172个RLMCriteria而不是258个!……还有什么问题?……)
解决方法
级联删除规则将在未来的版本中出现,但与此同时,您可以相当轻松地自己完成此操作.这是删除topo孩子的方法的更新版本:
- (void) removeObjects_at_TopoNr_from_LocationRLM :(NSUInteger)TopoNr :(NSString *)folderName :(NSString *)fileName { RLMRealm *realm = [RLMRealm realmWithPath:[self get_TopoResultRLM_FilePath :folderName :fileName]]; [realm beginWriteTransaction]; RLMResults *topos = [RLMTopoResult objectsInRealm:realm where:@"TopoNrRLM == %d",TopoNr]; for (RLMTopoResult *topo in topos) { [realm deleteObjects:topo.CriteriaRLM]; } [realm deleteObjects:topos]; [realm commitWriteTransaction]; }