我绝对是 Swift 和 Core Data 的新手。
我创建了一个两个实体的学习应用程序,没什么特别的。
我一直在寻找为什么(AFAICT)我的“Medicina”实体中的“Persona”选择器对象与“Persona”核心数据表中直接显示的对象不同;因为添加了一个谓词来使用从提到的选择器中获得的数据来过滤“Persona”核心数据表总是返回 0 个元素。
详情:
Personas 核心数据表显示了所有已添加到应用中的实体,没有任何问题,并且可以对其进行编辑。
当执行“PersonaTableViewController”中的以下代码时:
...
try self.fetchedResultsController.performFetch()
...
日志显示:
CoreData: sql: SELECT 0, t0.Z_PK, t0.Z_OPT, t0.ZCREATEDAT, t0.ZFECHANACIMIENTO, t0.ZMODIFIEDAT, t0.ZNOMBRE, t0.ZPESO FROM ZPERSONA t0 ORDER BY t0.ZCREATEDAT
CoreData: annotation: sql connection fetch time: 0.0006s
CoreData: annotation: fetch using NSSQLiteStatement <0x1c029abd0> on entity 'Persona' with sql text 'SELECT 0, t0.Z_PK, t0.Z_OPT, t0.ZCREATEDAT, t0.ZFECHANACIMIENTO, t0.ZMODIFIEDAT, t0.ZNOMBRE, t0.ZPESO FROM ZPERSONA t0 ORDER BY t0.ZCREATEDAT' returned 9 rows with values: (
"<Persona: 0x1c029a900> (entity: Persona; id: 0xd000000000040004 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p1> ; data: <fault>)",
"<Persona: 0x1c029a950> (entity: Persona; id: 0xd000000000080004 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p2> ; data: <fault>)",
"<Persona: 0x1c029b6c0> (entity: Persona; id: 0xd0000000000c0004 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p3> ; data: <fault>)",
"<Persona: 0x1c029a810> (entity: Persona; id: 0xd000000000100004 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p4> ; data: <fault>)",
"<Persona: 0x1c029a860> (entity: Persona; id: 0xd000000000140004 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p5> ; data: <fault>)",
"<Persona: 0x1c029b940> (entity: Persona; id: 0xd000000000180004 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p6> ; data: <fault>)",
"<Persona: 0x1c029a590> (entity: Persona; id: 0xd0000000001c0004 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p7> ; data: <fault>)",
"<Persona: 0x1c029a770> (entity: Persona; id: 0xd000000000200004 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p8> ; data: <fault>)",
"<Persona: 0x1c029b5d0> (entity: Persona; id: 0xd000000000240004 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p9> ; data: <fault>)"
)
CoreData: annotation: total fetch execution time: 0.0062s for 9 rows.
然后,用户需要在“Medicina”实体中选择一个“Persona”实体。于是,就有了Picker组件。
piker 中填充了这段代码:
func personaPickerInit(pPersonaPicker: UIPickerView) {
personaPicker.delegate = self
guard let managedObjectContext = managedObjectContext else { return }
let personasFetch = NSFetchRequest<NSFetchRequestResult>(entityName: "Persona")
let sort = NSSortDescriptor(key: "nombre", ascending: true)
personasFetch.sortDescriptors = [sort]
do {
let personaPickerObjects = try managedObjectContext.fetch(personasFetch) as! [Persona]
...
执行时,它会在日志中显示以下内容:
CoreData: sql: SELECT 0, t0.Z_PK, t0.Z_OPT, t0.ZCREATEDAT, t0.ZFECHANACIMIENTO, t0.ZMODIFIEDAT, t0.ZNOMBRE, t0.ZPESO FROM ZPERSONA t0 ORDER BY t0.ZNOMBRE
CoreData: annotation: sql connection fetch time: 0.0003s
CoreData: annotation: fetch using NSSQLiteStatement <0x1c4096c60> on entity 'Persona' with sql text 'SELECT 0, t0.Z_PK, t0.Z_OPT, t0.ZCREATEDAT, t0.ZFECHANACIMIENTO, t0.ZMODIFIEDAT, t0.ZNOMBRE, t0.ZPESO FROM ZPERSONA t0 ORDER BY t0.ZNOMBRE' returned 9 rows with values: (
"<Persona: 0x1c4093f60> (entity: Persona; id: 0xd000000000040002 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p1> ; data: <fault>)",
"<Persona: 0x1c4097070> (entity: Persona; id: 0xd000000000140002 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p5> ; data: <fault>)",
"<Persona: 0x1c4099a00> (entity: Persona; id: 0xd000000000180002 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p6> ; data: <fault>)",
"<Persona: 0x1c4099b90> (entity: Persona; id: 0xd0000000001c0002 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p7> ; data: <fault>)",
"<Persona: 0x1c4099be0> (entity: Persona; id: 0xd000000000200002 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p8> ; data: <fault>)",
"<Persona: 0x1c4099af0> (entity: Persona; id: 0xd000000000240002 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p9> ; data: <fault>)",
"<Persona: 0x1c4099c80> (entity: Persona; id: 0xd000000000100002 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p4> ; data: <fault>)",
"<Persona: 0x1c4099960> (entity: Persona; id: 0xd000000000080002 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p2> ; data: <fault>)",
"<Persona: 0x1c4099820> (entity: Persona; id: 0xd0000000000c0002 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p3> ; data: <fault>)"
)
CoreData: annotation: total fetch execution time: 0.0020s for 9 rows.
当需要让用户查看/编辑“Persona”详细信息时,我在 PersonaTableViewController
中添加了一个谓词所以它应该只显示一个“角色”。
我尝试在一个名为 personasFiltradas
的数组中传递整个对象使用以下谓词:
self.fetchedResultsController.fetchRequest.predicate = NSPredicate(format: "self IN %@", self.personasFiltradas);
与对应的日志:
CoreData: annotation: logically false fetch request <NSFetchRequest: 0x1c40ce770> (entity: Persona; predicate: (SELF IN {<Persona: 0x1c02994b0> (entity: Persona; id: 0xd000000000100002 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p4> ; data: {
createdAt = "1509640324.844775";
fechaNacimiento = 886399200;
medicinas = "<relationship fault: 0x1c423c640 'medicinas'>";
modifiedAt = 0;
nombre = "ggjfghcb jggjfhh hgjfjdj hfghfhfj utility uutsyifgu uyffuftjg. I I iuuuhhu Hugh";
peso = "207.8";
})}); sortDescriptors: ((
"(createdAt, ascending, compare:)"
)); type: NSManagedObjectResultType; ) short circuits.
CoreData: annotation: total fetch execution time: 0.0000s for 0 rows.
还尝试绕过 objectID
在一个名为 personasFiltradasIds
的数组中使用以下谓词:
self.fetchedResultsController.fetchRequest.predicate = NSPredicate(format: "Persona.objectID IN %@", self.personasFiltradasIds);
对应的日志显示:
CoreData: annotation: logically false fetch request <NSFetchRequest: 0x1c40cfea0> (entity: Persona; predicate: (Persona.objectID IN {0xd000000000100002 <x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p4>}); sortDescriptors: ((
"(createdAt, ascending, compare:)"
)); type: NSManagedObjectResultType; ) short circuits.
CoreData: annotation: total fetch execution time: 0.0000s for 0 rows.
如果您注意前面显示的两个“日志”条目,您可以看到相同的对象(路径如:<x-coredata://77904C2D-4B98-47DE-8A14-20A6F1CEB491/Persona/p1>
)具有不同的 ObjectID,因此网格始终为空,因为表中的对象以“4”,选择器中的那些以“2”结尾。 (实际上那些“id”一直在变化。问题是选择器上的那些总是与表中的不同)
我不确定我的诊断是否正确,但这是我能看到的。
如果能帮助我找出代码无法运行的原因,我们将不胜感激
编辑 1
我在这里添加模型。
最佳答案
我设法让它工作,但仍然无法理解为什么一个 Controller 获取与另一个 Controller “不同”的 Persona 对象:如果我在 MedicinaTableViewController
中获取“Persona”对象它不直接对应于 PersonaTableViewController
中的一个
我必须从 MedicinaTableViewController
发送“Persona”objectID 的 uri 表示至 PersonaTableViewController
vc.personasFiltradasUris = [medicina.persona!.objectID.uriRepresentation()]
然后取managedObjectId
来自 persistentStoreCoordinator
使用 forURIRepresentation
参数以便从 managedObjectContext
再次获取对象: object(with: oid)
var personasDesdeUris: [Persona] = []
for i in self.personasFiltradasUris {
let oid: NSManagedObjectID = self.persistentContainer.viewContext.persistentStoreCoordinator!.managedObjectID(forURIRepresentation: i)!
personasDesdeUris.append(self.persistentContainer.viewContext.object(with: oid) as! Persona)
print("+++++++ (PersTVC/ViewDidLoad/loadPersistentStores (Uris)) objid: ", oid, ", objid-UriRep: ", i)
}
self.fetchedResultsController.fetchRequest.predicate = NSPredicate(format: "self in %@", personasDesdeUris);
如果我在 MedicinaTableViewController
中这样做并发送一组 Persona 对象,它们仍然有错误的对象到 PersonaTableViewController
因此结果为空。
如有任何解释,我们将不胜感激。
编辑 1
忘了说,在两个 Controller 中,Persona 的 objectID.isTemporaryID
总是假的。所以这不是原因。
关于ios - Core Data swift3 primaryKey 相同但选择器中的 objectId 不同,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/48290548/