Using an existing SQLite database in MagicalRecord (swift) - ios

Question

I want my iOS swift app to preload existing sqlite file in MagicalRecord.
With reference to this, and others,
add sqlite, sqlite-shm, sqlite-wal file to my project, wrote some code in didFinishLaunchingWithOption like this.
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
// copy initial sqlite file to application directory
let preloadSQLiteURL:NSURL = NSURL(fileURLWithPath: NSBundle.mainBundle().pathForResource("myData", ofType: "sqlite")!)
let preloadShmURL:NSURL = NSURL(fileURLWithPath: NSBundle.mainBundle().pathForResource("myData", ofType: "sqlite-shm")!)
let preloadWalURL:NSURL = NSURL(fileURLWithPath: NSBundle.mainBundle().pathForResource("myData", ofType: "sqlite-wal")!)
let storeSQLiteURL:NSURL = NSPersistentStore.MR_urlForStoreName("myData.sqlite")
let storeShmURL:NSURL = NSPersistentStore.MR_urlForStoreName("myData.sqlite-shm")
let storeWalURL:NSURL = NSPersistentStore.MR_urlForStoreName("myData.sqlite-wal")
if !NSFileManager.defaultManager().copyItemAtURL(preloadSQLiteURL, toURL: storeSQLiteURL, error:&err) {
println("failed to copy sqlite file.")
}
if !NSFileManager.defaultManager().copyItemAtURL(preloadShmURL, toURL: storeShmURL, error:&err) {
println("failed to copy shm file.")
}
if !NSFileManager.defaultManager().copyItemAtURL(preloadWalURL, toURL: storeWalURL, error:&err) {
println("failed to copy wal file.")
}
MagicalRecord.setupCoreDataStackWithAutoMigratingSqliteStoreNamed("myData.sqlite")
return true
}
but copyItemAtURL all fails.
value of paths are these.
preloadSQLiteURL = file:///var/mobile/Applications/XXX/myApp.app/myData.sqlite
preloadShmURL = file:///var/mobile/Applications/XXX/myApp.app/myData.sqlite-shm
preloadWalURL = file:///var/mobile/Applications/XXX/myApp.app/myData.sqlite-wal
storeSQLiteURL = file:///var/mobile/Applications/XXX/Documents/myData.sqlite
storeShmURL = file:///var/mobile/Applications/XXX/Documents/myData.sqlite-shm
storeWalURL = file:///var/mobile/Applications/XXX/Documents/myData.sqlite-wal
my environment is Xcode6 beta7, iOS7.1.3.
Does anyone please help me? What should I do?
Any advice appreciated. Thanks in advance.

Answer 1

As a result, self-resolved.
NSError shows "The Operation couldn't be completed. (Cocoa error 516)"
Cocoa error 516 is "NSFileWriteFileExistsError" means "You can’t move a file to a place where a file already exists."
so, I corrected my code in this way.
let fileManager = NSFileManager.defaulManager()
let preloadSQLiteURL:NSURL = NSURL(fileURLWithPath: NSBundle.mainBundle().pathForResource("myData", ofType: "sqlite")!)
let storeSQLiteURL:NSURL = NSPersistentStore.MR_urlForStoreName("myData.sqlite")
if fileManager.fileExistsAtPath(storeSQLiteURL.path!) {
// file already exists, delete it and try again.
fileManager.removeItemAtURL(storeSQLiteURL, error:&err)
}
fileManager.copyItemAtURL(preloadSQLiteURL, toURL:storeSQLiteURL, error:nil)
and then, copyItemAtURL successfully completed and sqlite file takes effect.

Answer 2

While this is a poorly worded question, I'm assuming you want to load a SQLite database file from the app bundle into the user's documents directory so you can start with that data and then update it from there.
You're on the correct path, however, rather than copying all 3 files, when you create the default data store file, set your journal_mode to "DELETE" using the NSSQLitePragmasOption:
NSDictionary *options = #{NSSQLitePragmasOption: #{#"journal_mode": #"DELETE"}}
using this set of options when you add a persistent store to a coordinator when you're creating your default data set will only create a single SQLite file. From there, it'll be easier to copy only a single file over.
I also noticed in your code that you're copying myData.sqlite, but you're trying to load "acData.sqlite". Are you trying to load a file that isn't there?