Question

我尝试从两个实体中删除记录。核心数据有两个实体，名称Student和Detail都具有反比关系。关系是

学生 - ＆gt;细节：细节细节 - ＆gt;学生：学生

尝试从表格视图中删除两个实体的记录。但是当我尝试删除时，只有实体学生来自删除但来自详细实体才能删除。它告诉我这个错误。

- [NSSet isSubsetOfSet：]：set参数不是NSSet＆＃39;

DataAdapter.Fill()

StudentCoredataclass.h

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        // Delete the row from the data source

        AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
        _mainContext = [appDelegate manageObjectContext];

        [_mainContext deleteObject:[self.fetchedResultsController objectAtIndexPath:indexPath]];
        Detail *detailEntity = [self.fetchedResultsController objectAtIndexPath:indexPath];
        Student *studentEntity = [self.fetchedResultsController objectAtIndexPath:indexPath];

        NSMutableSet *mySet = [[NSMutableSet alloc] init];
        [mySet removeObject: detailEntity];
        [studentEntity removeDetail:mySet];
        studentEntity.detail = detailEntity;

        NSError *error = nil;
        if (![_mainContext save:&error]) {
            NSLog(@"Unresolve Error %@, %@", error, [error userInfo]);
            abort();
        }

        [self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];

    } 
}

DetailCoredataclass.h

#import "Student+CoreDataClass.h"


NS_ASSUME_NONNULL_BEGIN

@interface Student (CoreDataProperties)

+ (NSFetchRequest<Student *> *)fetchRequest;

@property (nullable, nonatomic, copy) NSString *name;
@property (nullable, nonatomic, copy) NSString *study;
@property (nullable, nonatomic, copy) NSString *number;
@property (nullable, nonatomic, retain) NSSet<Detail *> *detail;

@end

@interface Student (CoreDataGeneratedAccessors)

- (void)addDetailObject:(Detail *)value;
- (void)removeDetailObject:(Detail *)value;
- (void)addDetail:(NSSet<Detail *> *)values;
- (void)removeDetail:(NSSet<Detail *> *)values;

@end
NS_ASSUME_NONNULL_END

FetchedResultController：

#import "Detail+CoreDataClass.h"


NS_ASSUME_NONNULL_BEGIN

@interface Detail (CoreDataProperties)

+ (NSFetchRequest<Detail *> *)fetchRequest;

@property (nullable, nonatomic, copy) NSString *address;
@property (nullable, nonatomic, copy) NSString *contact;
@property (nullable, nonatomic, copy) NSString *email;
@property (nullable, nonatomic, copy) NSString *number;
@property (nullable, nonatomic, retain) Student *student;

@end

Answer 1

用以下代码替换您的代码：

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
        NSManagedObjectContext *context = [appDelegate manageObjectContext];
        Student *studentEntity = [self.fetchedResultsController objectAtIndexPath:indexPath];
        [context deleteObject:studentEntity];
         NSError *error = nil;
        [context save:&error];
    } 
}

接下来在模型中设置Delete Rule以在删除学生时删除详细信息（反之）。我不清楚为什么你有数据分成两个实体。

您不应在此处删除tableView的Cell。当你从fetchedResultsController获得委托回调时，你应该删除它。如果你还没有实现这些方法，那么现在就这样做。

Answer 2

请替换

[studentEntity removeDetail:mySet];

与

[studentEntity removeDetailObject:detailEntity];

尝试从核心数据中的两个实体中删除数据

2 个答案: