Ios 行的CoreData更新导致插入空行

我正在学习如何使用CoreData，并面临以下问题

我创建了这个函数，它应该更新现有行或插入新行。但当我试图更新现有的应用程序时，应用程序会插入一个空行

以下是我的部分代码：

func saveSettingToDatabase()
{
    guard settingNameLabel.text != nil else {return}

    let context = AppDelegate.viewContext
    let tableContext = SettingsTable(context: context)

    // Get record if already exists
    let request: NSFetchRequest<SettingsTable> = SettingsTable.fetchRequest()
    let searchString = settingNameLabel.text!
    request.predicate = NSPredicate(format: "settingName = %@", searchString)
    let fetchResult = try? context.fetch(request)

    //If record exists, update it. Else - insert.
    if fetchResult?.count == 1 {
        let change = fetchResult?[0]
        change?.setValue(settingNameLabel.text, forKey: "settingName")
        change?.setValue(settingValueLabel.text, forKey: "settingValue")
        change?.setValue(booleanValueSwich.isOn, forKey: "booleanValue")
        try? context.save()
    } else
    {
        tableContext.settingName = settingNameLabel.text
        tableContext.settingValue = settingValueLabel.text
        tableContext.booleanValue = booleanValueSwich.isOn
        context.insert(tableContext)
        try? context.save()
    }
}

但是我的程序从来没有在这里运行过。在我的课堂上没有其他的插页可以完成

---

有人能给我一些建议吗？

我觉得这个建议很有帮助： 因此，我在SettingsTable类中实现了awakeFromInsert函数。调试后，我可以看到insert已在此处初始化：

let tableContext = SettingsTable(context: context)

我已经将这一行移到else语句中，它现在可以正常工作了

func saveSettingToDatabase()
{
    guard settingNameLabel.text != nil else {return}

    let context = AppDelegate.viewContext

    // Get record if already exists
    let request: NSFetchRequest<SettingsTable> = SettingsTable.fetchRequest()
    let searchString = settingNameLabel.text!
    request.predicate = NSPredicate(format: "settingName = %@", searchString)
    let fetchResult = try? context.fetch(request)

    //If record exists, update it. Else - insert.
    if fetchResult?.count == 1 {
        let change = fetchResult?[0]
        change?.setValue(settingNameLabel.text, forKey: "settingName")
        change?.setValue(settingValueLabel.text, forKey: "settingValue")
        change?.setValue(booleanValueSwich.isOn, forKey: "booleanValue")
        try? context.save()
    } else
    {
        let tableContext = SettingsTable(context: context)
        tableContext.settingName = settingNameLabel.text
        tableContext.settingValue = settingValueLabel.text
        tableContext.booleanValue = booleanValueSwich.isOn
        context.insert(tableContext)
        try? context.save()
    }
}

func saveSettingToDatabase（）
{
guard settingNameLabel.text！=nil else{return}
让context=AppDelegate.viewContext
//获取已存在的记录
let请求：NSFetchRequest=SettingsTable.fetchRequest（）
让searchString=settingNameLabel.text！
request.predicate=NSPredicate（格式：“settingName=%@”，searchString）
让fetchResult=try？context.fetch（请求）
//如果记录存在，则更新它。否则-插入。
如果fetchResult？.count==1{
让更改=获取结果？[0]
更改？.setValue（settingNameLabel.text，forKey:“settingName”）
更改？.setValue（settingValueLabel.text，forKey:“settingValue”）
更改？.setValue（booleanValueSwich.isOn，forKey:“booleanValue”）
try？context.save（）
}否则
{
让tableContext=SettingsTable（上下文：context）
tableContext.settingName=settingNameLabel.text
tableContext.settingValue=settingValueLabel.text
tableContext.booleanValue=booleanValueSwich.isOn
context.insert（tableContext）
try？context.save（）
}
}

经过一些重构后，这个函数看起来更加清晰：

func saveSettingToDatabase()
{
    let context = AppDelegate.viewContext
    // Get record if already exists
    let request: NSFetchRequest<SettingsTable> = SettingsTable.fetchRequest()
    request.predicate = NSPredicate(format: "settingName = %@", settingNameTextField.text!)
    let fetchResult = try? context.fetch(request)

    //If record exists, update it. Else - insert.
    if fetchResult?.count == 1 {
        let change = fetchResult?[0]
        change?.settingName = settingNameTextField.text
        change?.settingValue = settingValueTextField.text
        change?.settingBooleanValue = settingBooleanValueSwitch.isOn
        try? context.save()
    } else
    {
        let addRecord = SettingsTable(context: context)
        addRecord.settingName = settingNameTextField.text
        addRecord.settingValue = settingValueTextField.text
        addRecord.settingBooleanValue = settingBooleanValueSwitch.isOn
        context.insert(addRecord)
        try? context.save()
    }
}

func saveSettingToDatabase（）
{
让context=AppDelegate.viewContext
//获取已存在的记录
let请求：NSFetchRequest=SettingsTable.fetchRequest（）
request.predicate=NSPredicate（格式：“settingName=%@”，settingNameTextField.text！）
让fetchResult=try？context.fetch（请求）
//如果记录存在，则更新它。否则-插入。
如果fetchResult？.count==1{
让更改=获取结果？[0]
更改？.settingName=settingNameTextField.text
更改？.settingValue=settingValueTextField.text
更改？.settingBooleanValue=settingBooleanValueSwitch.isOn
try？context.save（）
}否则
{
让addRecord=SettingsTable（上下文：上下文）
addRecord.settingName=settingNameTextField.text
addRecord.settingValue=settingValueTextField.text
addRecord.settingBooleanValue=settingBooleanValueSwitch.isOn
context.insert（addRecord）
try？context.save（）
}
}

func saveSettingToDatabase()
{
    let context = AppDelegate.viewContext
    // Get record if already exists
    let request: NSFetchRequest<SettingsTable> = SettingsTable.fetchRequest()
    request.predicate = NSPredicate(format: "settingName = %@", settingNameTextField.text!)
    let fetchResult = try? context.fetch(request)

    //If record exists, update it. Else - insert.
    if fetchResult?.count == 1 {
        let change = fetchResult?[0]
        change?.settingName = settingNameTextField.text
        change?.settingValue = settingValueTextField.text
        change?.settingBooleanValue = settingBooleanValueSwitch.isOn
        try? context.save()
    } else
    {
        let addRecord = SettingsTable(context: context)
        addRecord.settingName = settingNameTextField.text
        addRecord.settingValue = settingValueTextField.text
        addRecord.settingBooleanValue = settingBooleanValueSwitch.isOn
        context.insert(addRecord)
        try? context.save()
    }
}