Setting up
The simplest way to initialize CoreStore is to add a default store to the default stack:
do {
try CoreStore.addSQLiteStoreAndWait()
}
catch {
// ...
}This one-liner does the following:
- Triggers the lazy-initialization of
CoreStore.defaultStackwith a defaultDataStack - Sets up the stack's
NSPersistentStoreCoordinator, the root savingNSManagedObjectContext, and the read-only mainNSManagedObjectContext - Adds an automigrating SQLite store in the "Application Support" directory with the file name "[App bundle name].sqlite"
- Creates and returns the
NSPersistentStoreinstance on success, or anNSErroron failure
For most cases, this configuration is usable as it is. But for more hardcore settings, refer to this extensive example:
let dataStack = DataStack(modelName: "MyModel") // loads from the "MyModel.xcdatamodeld" file
do {
// creates an in-memory store with entities from the "Config1" configuration in the .xcdatamodeld file
let persistentStore = try dataStack.addInMemoryStore(configuration: "Config1") // persistentStore is an NSPersistentStore instance
print("Successfully created an in-memory store: \(persistentStore)"
}
catch let error as NSError {
print("Failed creating an in-memory store with error: \(error.description)"
}
do {
try dataStack.addSQLiteStoreAndWait(
fileURL: sqliteFileURL, // set the target file URL for the sqlite file
configuration: "Config2", // use entities from the "Config2" configuration in the .xcdatamodeld file
automigrating: true, // automatically run lightweight migrations or entity policy migrations when needed
resetStoreOnMigrationFailure: true)
print("Successfully created an sqlite store: \(persistentStore)"
}
catch let error as NSError {
print("Failed creating an sqlite store with error: \(error.description)"
}
CoreStore.defaultStack = dataStack // pass the dataStack to CoreStore for easier access later on(If you have never heard of "Configurations", you'll find them in your .xcdatamodeld file)
In our sample above, note that you don't need to do the CoreStore.defaultStack = dataStack line. You can just as well hold a reference to the DataStack like below and call all its instance methods directly:
class MyViewController: UIViewController {
let dataStack = DataStack(modelName: "MyModel")
override func viewDidLoad() {
super.viewDidLoad()
do {
try self.dataStack.addSQLiteStoreAndWait()
}
catch { // ...
}
}
func methodToBeCalledLaterOn() {
let objects = self.dataStack.fetchAll(From(MyEntity))
print(objects)
}
}The difference is when you set the stack as the CoreStore.defaultStack, you can call the stack's methods directly from CoreStore itself:
class MyViewController: UIViewController {
override func viewDidLoad() {
super.viewDidLoad()
do {
try CoreStore.addSQLiteStoreAndWait()
}
catch { // ...
}
}
func methodToBeCalledLaterOn() {
let objects = CoreStore.fetchAll(From(MyEntity))
print(objects)
}
}