删除所有 Core Data 数据

[jaywcjlove]

let entities = PersistenceController.shared.container.managedObjectModel.entities
for entity in entities {
    if ((entity.name) != nil) {
        let deleteFetch = NSFetchRequest<NSFetchRequestResult>(entityName: entity.name!)
        let deleteRequest = NSBatchDeleteRequest(fetchRequest: deleteFetch)

        do {
            try viewContext.execute(deleteRequest)
            try viewContext.save()
        } catch {
            print ("There was an error")
        }
    }
}