Swift 5 Nsfetchrequest谓词尝试查找字符串UUID

发布于 2025-02-03 17:09:26 字数 775 浏览 2 评论 0原文

我有一个字符串的UUID进入此方法，以查找Coredata中的一个实体，该实体将UUID保存为UUID类型（不是字符串）。

我不断遇到“致命错误：在谓词上拆开可选值时出乎意料地发现了无效”。

func loadUser(uuid: String) -> [ExistingUsers2] {
    let request : NSFetchRequest<ExistingUsers2> = ExistingUsers2.fetchRequest()
    let uuidQuery = NSUUID(uuidString: uuid)
    request.predicate = NSPredicate(format: "%K == %@", #keyPath(ExistingUsers2.uuid), uuidQuery! as CVarArg)
    request.sortDescriptors = [NSSortDescriptor(key: "name", ascending: true)]
    do {
        existingUsersArray = try context.fetch(request)
        print("Returned \(existingUsersArray.count)")
    } catch {
        print("Error fetching data from context \(error)")
    }
    return existingUsersArray
}

有帮助吗？我在这里什么都没找到或Google博士。 TKS

原文

I have a string UUID coming into this method, to lookup an entity in CoreData that has UUID's saved as UUID type (Not String).

I keep getting "Fatal error: Unexpectedly found nil while unwrapping an Optional value" on line for the predicate.

func loadUser(uuid: String) -> [ExistingUsers2] {
    let request : NSFetchRequest<ExistingUsers2> = ExistingUsers2.fetchRequest()
    let uuidQuery = NSUUID(uuidString: uuid)
    request.predicate = NSPredicate(format: "%K == %@", #keyPath(ExistingUsers2.uuid), uuidQuery! as CVarArg)
    request.sortDescriptors = [NSSortDescriptor(key: "name", ascending: true)]
    do {
        existingUsersArray = try context.fetch(request)
        print("Returned \(existingUsersArray.count)")
    } catch {
        print("Error fetching data from context \(error)")
    }
    return existingUsersArray
}

Any help? I haven't found anything here or Dr Google. TKS

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小镇女孩 2025-02-10 17:09:26

您可以用以下方式替换谓词：

guard let uuidQuery = UUID(uuidString: uuid) else { return [] } // no valid UUID with this code
request.predicate = NSPredicate(format: "%K == %@", #keyPath(ExistingUsers2.uuid), uuidQuery as CVarArg)

其他所有内容都应起作用。

更新

这是最终有效的代码，感谢您的帮助 @andréHenriqueda Silva

func loadUser(uuid: String) -> [ExistingUsers2] {
    let request : NSFetchRequest<ExistingUsers2> = ExistingUsers2.fetchRequest()
    let uuidQuery = NSUUID(uuidString: uuid)
    request.predicate = NSPredicate(format: "uuid == %@", uuidQuery! as CVarArg)
    request.sortDescriptors = [NSSortDescriptor(key: "name", ascending: true)]
    do {
        existingUsersArray = try context.fetch(request)
    } catch {
        print("Error fetching data from context \(error)")
    }
    return existingUsersArray
}

You can replace your predicate with this:

guard let uuidQuery = UUID(uuidString: uuid) else { return [] } // no valid UUID with this code
request.predicate = NSPredicate(format: "%K == %@", #keyPath(ExistingUsers2.uuid), uuidQuery as CVarArg)

Everything else should work.

UPDATE

This is the code that finally worked, thanks for your help @André Henrique da Silva

func loadUser(uuid: String) -> [ExistingUsers2] {
    let request : NSFetchRequest<ExistingUsers2> = ExistingUsers2.fetchRequest()
    let uuidQuery = NSUUID(uuidString: uuid)
    request.predicate = NSPredicate(format: "uuid == %@", uuidQuery! as CVarArg)
    request.sortDescriptors = [NSSortDescriptor(key: "name", ascending: true)]
    do {
        existingUsersArray = try context.fetch(request)
    } catch {
        print("Error fetching data from context \(error)")
    }
    return existingUsersArray
}

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千秋岁 2025-02-10 17:09:26

尝试以您的谓词：nspredicate（格式：“ cid =％@”，“ \（id）”）

其中cid是uuid在中，Coredata和ID是您从字符串中获得的UUID。也不使用nsuuid。

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独木成林 2025-02-10 17:09:26

用您的属性名称替换uuidattributename yourstringuuid ，用要转换为UUID类型的字符串。

var uuid = UUID(uuidString: yourStringuuid)

let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "ExistingUsers2")
fetchRequest.predicate = NSPredicate(format: "uuidAttributeName == %@",uuid)

let results = try context.fetch(fetchRequest)

Replace the uuidAttributeName with your attribute name and yourStringuuid with the your string that you want to convert into UUID type.

var uuid = UUID(uuidString: yourStringuuid)

let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName: "ExistingUsers2")
fetchRequest.predicate = NSPredicate(format: "uuidAttributeName == %@",uuid)

let results = try context.fetch(fetchRequest)

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