一对多关系解析

Question

我已经翻遍了，但我找不到这个问题的答案。

我正在将 Podcast 及其相关剧集保存到 Parse，但以下代码仅保存 1 集和播客（我想在 for 循环中找到的每个条目都会重置 currentP 并且只保存找到的最后一个值）。

 let currentP = PFObject(className: self.podcastClass)
    currentP["user"] = PFUser.currentUser()
    currentP["name"] = name
    currentP["artist"] = artist
    currentP["summary"] = summary
    currentP["feedURL"] = feedURL
    currentP["artworkURL"] = artworkURL
    currentP["artwork"] = artwork
    currentP["date"] = date

 let episodesToParse = PFObject(className: self.episodesClass)
    for episode in episodes {
    episodesToParse["showDate"] = episode.date
    episodesToParse["title"] = episode.title          
    episodesToParse["downloadURL"] =  episode.enclosures[0].valueForKey("url") as? String
    episodesToParse["showNotes"] = episode.summary
    episodesToParse["localPath"] = ""
    episodesToParse["isDownloaded"] = "no"
    episodesToParse["parent"] = currentP
}
 episodesToParse.saveInBackground()

如果我使用episodesToParse.addObject(episode.date, forKey: "showDate") 之类的内容，则会返回以下错误：

[Error]: invalid type for key showDate, expected date, but got array (Code: 111, Version: 1.8.1)

我不确定如何继续。我想要的是按原样保存 currentP，并将其所有剧集保存在与其父级（播客）有关系的不同类中。如果您一次添加一集而不是一大堆，我找到了很多方法来做到这一点（我希望能够一次保存 500 个 episodesToParse 实例。

感谢您的帮助。

Answer 1

您的问题是，您在循环之后保存了episodesToParse。您必须在循环内移动episodesToParse.saveInBackground()，以便每次循环设置剧集的属性时，剧集都会更新：

for episode in episodes {
    episodesToParse["showDate"] = episode.date
    episodesToParse["title"] = episode.title          
    episodesToParse["downloadURL"] =  episode.enclosures[0].valueForKey("url") as? String
    episodesToParse["showNotes"] = episode.summary
    episodesToParse["localPath"] = ""
    episodesToParse["isDownloaded"] = "no"
    episodesToParse["parent"] = currentP

    //Inside
    episodesToParse.saveInBackground()
}

或者您可以使用PFObject.saveAllInBackground 来保存所有对象：

var episodesToSave[PFObject] = []

for episode in episodes {
    var episodeToParse
    episodeToParse["showDate"] = episode.date
    episodeToParse["title"] = episode.title          
    episodeToParse["downloadURL"] =  episode.enclosures[0].valueForKey("url") as? String
    episodeToParse["showNotes"] = episode.summary
    episodeToParse["localPath"] = ""
    episodeToParse["isDownloaded"] = "no"
    episodeToParse["parent"] = currentP

    //Add to episode-array
    episodesToSave.append(episodesToParse)
}

//Save all objects in the array
PFObject.saveAllInBackground(episodesToSave)