iOS sqlcipher fmdb文件已加密或不是数据库

这 tutorial 使用以下代码即可正常工作。

pod 'FMDB/SQLCipher'

...

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
...

    NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentDir = [documentPaths objectAtIndex:0];
    self.databasePath = [documentDir stringByAppendingPathComponent:@"gameDefault.sqlite"];

    [self createAndCheckDatabase];

...
}

...

-(void) createAndCheckDatabase
{
    BOOL success;

    NSFileManager *fileManager = [NSFileManager defaultManager];
    success = [fileManager fileExistsAtPath:self.databasePath];

    if(success) return; // If file exists, dont do anything

    // if file does not exist, make a copy of the one in the Resources folder
    NSString *databasePathFromApp = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"gameDefault.sqlite"]; // File path

    [fileManager copyItemAtPath:databasePathFromApp toPath:self.databasePath error:nil]; // Make a copy of the file in the Documents folder

    // Set the new encrypted database path to be in the Documents Folder
    NSArray *documentPaths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentDir = [documentPaths objectAtIndex:0];
    NSString *ecDB = [documentDir stringByAppendingPathComponent:@"encrypted.sqlite"];

    // SQL Query. NOTE THAT DATABASE IS THE FULL PATH NOT ONLY THE NAME
    const char* sqlQ = [[NSString stringWithFormat:@"ATTACH DATABASE '%@' AS encrypted KEY 'secretKey';",ecDB] UTF8String];

    sqlite3 *unencrypted_DB;    
    if (sqlite3_open([self.databasePath UTF8String], &unencrypted_DB) == SQLITE_OK) {

        // Attach empty encrypted database to unencrypted database
        sqlite3_exec(unencrypted_DB, sqlQ, NULL, NULL, NULL);

        // export database
        sqlite3_exec(unencrypted_DB, "SELECT sqlcipher_export('encrypted');", NULL, NULL, NULL);

        // Detach encrypted database
        sqlite3_exec(unencrypted_DB, "DETACH DATABASE encrypted;", NULL, NULL, NULL);

        sqlite3_close(unencrypted_DB);
    } else {
        sqlite3_close(unencrypted_DB);
        NSAssert1(NO, @"Failed to open database with message '%s'.", sqlite3_errmsg(unencrypted_DB));
    }

    self.databasePath = [documentDir stringByAppendingPathComponent:@"encrypted.sqlite"];
}

...

[db setKey:@"secretKey"]

...

   // FMDatabase
    FMDatabase *db = [FMDatabase databaseWithPath:[self getDatabasePath]];
    [db open];
    [db setKey:@"secretKey"];

    // FMDatabaseQueue
    FMDatabaseQueue *queue = [FMDatabaseQueue databaseQueueWithPath:[self getDatabasePath]];

    [queue inDatabase:^(FMDatabase *db) {
        [db setKey:@"secretKey"];
        ...
    }];

...

当我在其他项目中使用相同的代码时,它可以很好地加密现有的sqlite数据库。 但当我试图通过sql select查询访问表时,我得到了错误,“文件已加密或不是数据库”。 不过,教程应用程序没有问题,我可以在那里更新/插入/删除/选择记录。有线索吗?