Swift GRDB 写入数据库错误 "attempt to write a readonly database"

Question

我正在尝试写入我创建的报价数据库。如果用户选择“收藏夹”按钮，它将在 SQLITE 数据库的收藏夹列中添加一个 1(或真)值。由于某种原因，我无法写入数据库，当我执行此代码时:

    @IBAction func addFavorite(_ sender: Any) {
        var configuration = Configuration()
        configuration.readonly = false
        let dbPath = Bundle.main.path(forResource: "data", ofType: "db")!
        let dbQueue = try! DatabaseQueue(path: dbPath, configuration: configuration)

        try! dbQueue.inDatabase { db in
            try db.execute("""
UPDATE quotes SET favorite = 1 WHERE quote = ?;
""",
                                           arguments: [quoteLabel.text])
    }

我希望结果写入数据库并在最喜欢的列中放置一个 1，但遗憾的是情况并非如此。我收到此错误:

Thread 1: Fatal error: 'try!' expression unexpectedly raised an error: SQLite error 8 with statement UPDATE quotes SET favorite = 1 WHERE quote = ? arguments ["Abstinence is the great strengthener and clearer of reason."]: attempt to write a readonly database

我已经尝试 chmod 755 数据库，但也没有用。我错过了什么吗？

Answer 1

数据库的路径就是应用程序资源的路径。 iOS 无法修改应用资源。

参见 File System Basics了解更多信息。特别相关的引用:

[...] the app’s bundle. This directory contains the app and all of its resources.

You cannot write to this directory. To prevent tampering, the bundle directory is signed at installation time. Writing to this directory changes the signature and prevents your app from launching. You can, however, gain read-only access to any resources stored in the apps bundle. For more information, see the Resource Programming Guide.

现在，如果无法修改，您如何在数据库中写入？

嗯，你把它复制到一个可以修改的地方。您永远不会修改捆绑的数据库资源，只会修改副本。

再次有可用文档:How do I open a database stored as a resource of my application? GRDB 常见问题解答说:

If the application should modify the database resource, you need to copy it to a place where it can be modified. For example, in the Application Support directory. Only then, open a connection:

let fileManager = FileManager.default

let dbPath = try fileManager
    .url(for: .applicationSupportDirectory, in: .userDomainMask, appropriateFor: nil, create: true)
    .appendingPathComponent("db.sqlite")
    .path

if !fileManager.fileExists(atPath: dbPath) {
    let dbResourcePath = Bundle.main.path(forResource: "db", ofType: "sqlite")!
    try fileManager.copyItem(atPath: dbResourcePath, toPath: dbPath)
}

let dbQueue = try DatabaseQueue(path: dbPath)