Sample code cut from some messing with SecureLoginDelegate for a SQLCipher iOS tutorial

SecureLoginDelegate-AppDelegate.m

//
//  AppDelegate.m
//  SecureLoginDelegate
//
//  Created by Billy Gray on 10/19/14.
//  Copyright (c) 2014 Zetetic. All rights reserved.
//

#import "AppDelegate.h"
#import <sqlite3.h>

@interface AppDelegate ()
@property (nonatomic) BOOL isLoginViewControllerDisplayed;
@property (readonly) NSURL *databaseURL;
@property (readonly) BOOL databaseExists;
@end

@implementation AppDelegate
@dynamic databaseURL;
@dynamic databaseExists;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Set up the window with loginViewController as the rootViewController for now
    // to avoid showing app view on launch on iOS 8
    [[self window] setRootViewController:self.loginViewController];
    [[self window] makeKeyAndVisible];
    self.isLoginViewControllerDisplayed = YES;
    
    // Set up a SQLCipher database connection:
    sqlite3 *db;
    if (sqlite3_open([[self.databaseURL path] UTF8String], &db) == SQLITE_OK) {
        const char* key = [@"StrongPassword" UTF8String];
        sqlite3_key(db, key, (int)strlen(key));
        if (sqlite3_exec(db, (const char*) "SELECT count(*) FROM sqlite_master;", NULL, NULL, NULL) == SQLITE_OK) {
            NSLog(@"Password is correct, or a new database has been initialized");
        } else {
            NSLog(@"Incorrect password!");
        }
        sqlite3_close(db);
    }
    return YES;
}

- (NSURL *)databaseURL {
    NSArray *URLs = [[NSFileManager defaultManager] URLsForDirectory:NSDocumentDirectory inDomains:NSUserDomainMask];
    NSURL *directoryURL = [URLs firstObject];
    NSURL *databaseURL = [directoryURL URLByAppendingPathComponent:@"secure.db"];
    return  databaseURL;
}

- (BOOL)databaseExists {
    BOOL exists = NO;
    NSError *error = nil;
    exists = [[self databaseURL] checkResourceIsReachableAndReturnError:&error];
    if (exists == NO && error != nil) {
        NSLog(@"Error checking availability of database file: %@", error);
    }
    return exists;
}

@end