swift 删除核心数据元素

hwamh0ep 于 2023-08-02 发布在 Swift

关注(0)|答案(4)|浏览(113)

我正试图实现一个功能，以删除闪存卡在一组自定义闪存卡，但我有麻烦的CoreData方面的。这应该做的是循环通过保存的卡，如果它与要删除的卡匹配，那么我们将从当前卡组中删除它并保存上下文，有人知道出了什么问题吗？使用断点，我可以确认if语句确实执行了，因此它具有内部逻辑

do {
    self.fetchedCards = try context.fetch(Cards.fetchRequest())
    for card in self.fetchedCards {
        if(self.termLabel.text == card.term){
        self.managedDeck?.removeFromCards(card)
        ad.saveContext()
        break
        }
     }
 } catch {
   }

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swift

来源：https://stackoverflow.com/questions/60157552/deleting-core-data-element

4条答案

按热度按时间

eeq64g8w1#

请使用此功能删除核心数据中的所有数据

func deleteAllData(entity: String) {
    let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
    let managedContext = appDelegate.managedObjectContext
    let fetchRequest = NSFetchRequest(entityName: entity)
    fetchRequest.returnsObjectsAsFaults = false

    do {
        let results = try managedContext.executeFetchRequest(fetchRequest)
        for managedObject in results
        {
            let managedObjectData:NSManagedObject = managedObject as! NSManagedObject
            managedContext.deleteObject(managedObjectData)
            print("Deleted")
        }
    } catch let error as NSError {
        print(error)
    }
}

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w6lpcovy2#

删除所有数据可以使用此函数

func deleteAllData(entity: String) {

    let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
    let managedContext = appDelegate.managedObjectContext
    let fetchRequest = NSFetchRequest(entityName: entity)
    fetchRequest.returnsObjectsAsFaults = false

    do
    {
        let results = try managedContext.executeFetchRequest(fetchRequest)
        for managedObject in results
        {
            let managedObjectData:NSManagedObject = managedObject as! NSManagedObject
            managedContext.deleteObject(managedObjectData)
            print("Deleted")
        }

    } catch let error as NSError {
        print(error)
    }
}

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用途：

deleteAllData(entity: "your Entity name")

型

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ipakzgxi3#

var cards = try! context.fetch(Cards.fetchRequest())

for card in cards {
    if (self.termLabel.text == card.term) {
        context.delete(card)
    }
}
try! context.save()

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iaqfqrcu4#

在if语句中，我需要context.delete(card)而不是self.managedDeck?.removeFromCards(card)

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