如题 我已经设定好relation 算是蛮简单的练习而已 不过不知道为何我用sql看coredata的资料库时,发现并没有正确的帮我建立对应关系 例如 一个Album只能有一个singer 一个singer可以有很多个Album 然後我去建立资料 singer:A Album:01 singer:A Album:02 singer:A Album:03 这时去看sql资料应该要是 pk singer 1 A 2 A 3 A pk Album singer 1 01 1 2 02 1 3 03 1 但是我跑出来的都是 pk singer 1 A 2 A 3 A pk Album singer 1 01 1 2 02 2 3 03 3 虽然Album有建立与singer的relation,而且最後出来的singer都是Ａ 但是总觉得哪里怪怪的,跟期待的不一样,原本期待singer(key)都只会是1而已 好像coredata并没有帮我搜寻我建立的singer是不是重复的 没有在建立关系时帮我统一对应到一个 这是本来受这样吗？还是我哪边可能有出错呢？ coredata是用xcdatamodel建立的 我检查singer跟album的relation有箭头互相指 ---------------------- @interface Album (CoreDataProperties) @property (nullable, nonatomic, retain) NSString *album_name; @property (nullable, nonatomic, retain) Singer *singer; @end ----------------------- @interface Singer (CoreDataProperties) @property (nullable, nonatomic, retain) NSString *name; @property (nullable, nonatomic, retain) NSSet<Album *> *album; @end ----------------------- Singer *singer = [self.appDelegate creatSinger]; singer.name = self.singerField.text; Album *album = [self.appDelegate creatAlbum]; album.album_name = self.albumField.text; album.singer = singer; //建立album与singer关系 ----------------------- - (Singer *) creatSinger { NSManagedObjectContext *moc = [self managedObjectContext]; Singer *singer = [NSEntityDescription insertNewObjectForEntityForName:@"Singer" inManagedObjectContext:moc]; return singer; } - (Album *) creatAlbum { NSManagedObjectContext *moc = [self managedObjectContext]; Album *album = [NSEntityDescription insertNewObjectForEntityForName:@"Album" inManagedObjectContext:moc]; return album; } --

※ 发信站: 批踢踢实业坊(ptt.cc), 来自: 123.241.102.252 ※ 文章网址: https://webptt.com/cn.aspx?n=bbs/MacDev/M.1475524374.A.46E.html ※ 编辑: wrt (123.241.102.252), 10/04/2016 04:08:32