[問題] CoreData relationship predicate

看板MacDev作者whitefur (白毛)時間11年前 (2013/11/21 10:55)推噓0(0推 0噓 3→)

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現有一個Entity為CompletdFrame 它有一個to-many relationship為peopleRead 欲fetch出 peopleRead個數為0的CompletedFrame NSFetchRequest *fr = [NSFetchRequest fetchRequestWithEntityName:@"CompletedFrame"]; //只fetch peopleRead個數為0的CompletedFrame fr.predicate = [NSPredicate predicateWithFormat:@"peopleRead.@count == 0"]; NSArray *framesIHaveNotRead = [_appDelegate.managedObjectContext executeFetchRequest:fr error:&error]; 但是把framesIHaveNotRead印出來卻有peopleRead個數不為0的CompletedFrame 是因為predicate不能針對relationship嗎？ <CompletedFrame: 0x1427c750> (entity: CompletedFrame; id: 0x1427ab00 <x-coredata://4FF961E4-8C79-488A-BB14-7A640F28A095/CompletedFrame/p7> ; data: { fid = e9f527cc7a; order = 0; peopleRead = ( "0xc8726d0 <x-coredata://4FF961E4-8C79-488A-BB14-7A640F28A095/Friend/p1 ); readIconHidden = 0; receiver = "0x14271710 <x-coredata://4FF961E4-8C79-488A-BB14-7A640F28A095/Receiver/p6>"; sender = "0x1267d170 <x-coredata://4FF961E4-8C79-488A-BB14-7A640F28A095/Friend/p4>"; sendingStatus = 2; stickerTexts = ( "0x1827a870 <x-coredata://4FF961E4-8C79-488A-BB14-7A640F28A095/CompletedStickerText/p7>" ); timestamp = "2013-11-21 02:35:08 +0000"; type = 1; works = "<relationship fault: 0xc879e10 'works'>"; }) ) -- ※ 發信站: 批踢踢實業坊(ptt.cc) ◆ From: 1.160.26.33