Objective c 目标c中的Sqlite3查询

这里没有， 在NSLog上，我可以打印“SelectAccessCodefromUserAccess”，比如说访问代码是1234，这是我想要的 1234从数据表UserAccess.sqlite中的UserAccess表中的AccessCode列 我的数据库和表名是相同的oops。 在appdelegate中，我有： ///

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请提供帮助：（

您需要进行一些sqlite3调用以执行select语句并检索列值

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包含此特定任务所需的所有信息。

您应该使用Objective-C字符串常量

NSString*sqlns=@“SELECT ACCESS code FROM UserAccess”；

而不是从正在使用的C字符串生成Objective-C字符串的复杂方法。我需要NSLog中“ACCESS code”列的值(@“%@”，sqlns）；我应该获取1234而不是：从UserAccess中选择AccessCode

  -(IBAction)ButtonPressed:(id)sender
    { 
        const char *sql = "SELECT AccessCode FROM UserAccess";
        NSString *sqlns;
        sqlns = [NSString stringWithUTF8String:sql];
        if([Password.text isEqual:sqlns])
        {
            NSLog(@"Correct");
        }
            else {
                NSLog(@"Wrong");
            }

    NSLog(@"%@",sqlns);
    }

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

    // Override point for customization after app launch 
    [self createEditableCopyOfDatabaseIfNeeded];    
    [window addSubview:viewController.view];
    [window makeKeyAndVisible];

    return YES;
}

 - (void)createEditableCopyOfDatabaseIfNeeded {

        NSLog(@"Creating editable copy of database");

        // First, test for existence.

        BOOL success;

        NSFileManager *fileManager = [NSFileManager defaultManager];

        NSError *error;

        NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

        NSString *documentsDirectory = [paths objectAtIndex:0];

        NSString *writableDBPath = [documentsDirectory stringByAppendingPathComponent:@"UserAccess.sqlite"];

        success = [fileManager fileExistsAtPath:writableDBPath];

        if (success) return;

        // The writable database does not exist, so copy the default to the appropriate location.

        NSString *defaultDBPath = [[[NSBundle mainBundle] resourcePath] stringByAppendingPathComponent:@"UserAccess.sqlite"];

        success = [fileManager copyItemAtPath:defaultDBPath toPath:writableDBPath error:&error];

        if (!success) {

            NSAssert1(0, @"Failed to create writable database file with message '%@'.", [error localizedDescription]);

        }

    }

+(sqlite3 *) getNewDBConnection{

    sqlite3 *newDBconnection;

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);

    NSString *documentsDirectory = [paths objectAtIndex:0];

    NSString *path = [documentsDirectory stringByAppendingPathComponent:@"UserAccess.sqlite"];

    // Open the database. The database was prepared outside the application.

    if (sqlite3_open([path UTF8String], &newDBconnection) == SQLITE_OK) {

        NSLog(@"Database Successfully Opened :) ");

    } else {

        NSLog(@"Error in opening database :( ");

              }

              return newDBconnection;

              }