如何创建自定义领域文件

Question

我正在像这样初始化我的领域实例：

private static let sUserRealm:Realm = try! Realm(configuration:Realm.Configuration(
        fileURL: Bundle.main.url(forResource: "user" ,withExtension: "realm"),
        inMemoryIdentifier: nil,
        syncConfiguration: nil,
        encryptionKey: nil,
        readOnly: false,
        schemaVersion: 0,
        migrationBlock: sMigrationBlock,
        deleteRealmIfMigrationNeeded: true,
        objectTypes: nil))

但是，我遇到了这个错误：

fatal error: A Realm Configuration must specify a path or an in-memory 
identifier.: file /Users/realm/workspace/Package iOS Swift/tightdb_objc/RealmSwift/RealmConfiguration.swift, line 201

所有领域在其关于创建多个领域的快速文档中都有this 示例，即使逐字复制也会引发相同的错误。如何创建和访问领域文件？

Answer 1

Swift 5：

只需自定义您的领域文件的名称

struct Kingdom {
    static let persist = Kingdom()

    let realm: Realm = { () -> Realm in
        var config = Realm.Configuration()
        config.fileURL = config.fileURL!.deletingLastPathComponent().appendingPathComponent("deng.realm")
        let land = try! Realm(configuration: config)
        return land
    }()
}

---

自定义您的领域文件的名称和路径

struct Kingdom {
    static let persist = Kingdom()

    let realm: Realm = { () -> Realm in
        let paths = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true)
        let documentsDirectory = paths[0]
        let docURL = URL(string: documentsDirectory)!
        let dataPath = docURL.appendingPathComponent("Dng")
        if FileManager.default.fileExists(atPath: dataPath.absoluteString) == false{
            do {
                try FileManager.default.createDirectory(atPath: dataPath.absoluteString, withIntermediateDirectories: true, attributes: nil)
            } catch {
                print(error.localizedDescription)
            }
        }
        do {
            var config = Realm.Configuration()
            config.fileURL = dataPath.appendingPathComponent("deng.realm")
            let realmReal = try Realm(configuration: config)
            return realmReal
        } catch {
            print(error.localizedDescription)
            let realmForSyntax = try! Realm()
            return realmForSyntax
        }
    }()
}

Answer 2

Bundle.url(forResource:withExtension:) 返回给定包中现有文件的路径。您链接到的领域文档部分使用了在您的应用程序包中包含领域文件的示例。

由于您似乎正试图在特定路径上创建一个新 Realm 文件，您应该计算该路径并将其设置为Realm.Configuration 上的fileURL。您通常不想为此使用Bundle API，因为您的应用程序包中的文件不可写。相反，您应该构建一个相对于您应用的文档或缓存目录的路径：

let documentDirectory = FileManager.default.url(for: .documentDirectory, in: .userDomainMask,
                                                appropriateFor: nil, create: false)
let url = documentDirectory.appendingPathComponent("my-new-realm.realm")

Answer 3

这是一个示例 Realm 配置类，每个配置创建一个新的 Realm 文件。

     import Foundation
     import RealmSwift

     class RealmConfiguration {

// Create "default.realm" in document file
        public static var defaultDataConfiguration = Realm.Configuration.defaultConfiguration

// Create "insensitive.realm"
        static func insensitiveDataConfiguration() -> Realm.Configuration {
            var config = Realm.Configuration()
            config.fileURL = config.fileURL!.deletingLastPathComponent().appendingPathComponent("insensitive.realm")
            return config
        }

// Create "sensitive.realm"
        static func sensitiveDataConfiguration() -> Realm.Configuration {
            var config = Realm.Configuration()
            config.fileURL = config.fileURL!.deletingLastPathComponent().appendingPathComponent("sensitive.realm")
            return config
        }
    }

Answer 4

使用 Bundle.main.url(forResource: "user" ,withExtension: "realm")! 但这个值可能是 nil 因为你的文件不存在

而不是 Bundle.main.url(forResource: "user" ,withExtension: "realm")

小心设置

编辑

要使用预定义的数据库，您可以使用Bundle。

但如果您想为您的应用使用新数据库，请使用其他路径。不捆绑。

https://realm.io/docs/swift/latest/

var config = Realm.Configuration()

  // Use the default directory, but replace the filename with the username
  config.fileURL = config.fileURL!.deletingLastPathComponent()
                         .appendingPathComponent("\(username).realm")

比

sUserRealm:Realm = try! Realm(configuration:config)

或您想要的任何路径，但不是Bundle。

创建和编辑文件和目录：

let fileManager:FileManager = FileManager.default
        let documentdir:String = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).last!

        let dbName = someDataBaseFileName

        let yourFullFileName = String(format:"%@/%@",documentdir,dbName)

//或

let yourFullPath:String = URL(fileURLWithPath: documentdir).appendingPathComponent(dbName).path