iphone - 谁能告诉我为什么我的代码无法创建数据库和表，然后在其中存储数据。

Question

因此，我的代码假设是创建一个数据库和表，然后将我的位置数据存储在表中。它会击中我创建的所有正确日志，例如“创建表”和“插入位置”，但是当我去查找文件时，它要么（a）不存在，要么（b）那里但没有位置数据。

我开始使用CoreData，但是它很快变成了一场噩梦，因此我改为直接使用sqlite。

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

        locationManager =[[CLLocationManager alloc] init];

        locationManager.delegate = self; 
        locationManager.desiredAccuracy = kCLLocationAccuracyBest;
        locationManager.distanceFilter = 10;
        [locationManager startUpdatingLocation]; 



// Create a string containing the full path to the bold2.db inside the documents folder
    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
    NSString *documentsDirectory = [paths objectAtIndex:0];
    NSString *databasePath = [documentsDirectory stringByAppendingPathComponent:@"bold2.sql"];

    // Check to see if the database file already exists
    bool databaseAlreadyExists = [[NSFileManager defaultManager] fileExistsAtPath:databasePath];

    // Open the database and store the handle as a data member
    if (sqlite3_open([databasePath UTF8String], &databasehandle) == SQLITE_OK)
    {
        // Create the database if it doesn't yet exists in the file system
        if (!databaseAlreadyExists)
        {
            // Create the LOCATION table
            const char *sqlStatement = "CREATE TABLE IF NOT EXISTS LOCATION (ID INTEGER PRIMARY KEY AUTOINCREMENT, latitude DOUBLE, longitude DOUBLE, timeStamp DATE)";
            char *error;
            if (sqlite3_exec(databasehandle, sqlStatement, NULL, NULL, &error) == SQLITE_OK)
          {
                NSLog(@"Created Table");
                 }
              }

这是位置代表，我在这里获取新位置并将其插入数据库。奇怪的是，它实际上命中了“插入位置”日志。

    -(void) locationManager: (CLLocationManager *) manager
    didUpdateToLocation: (CLLocation *) newLocation
           fromLocation: (CLLocation *) oldLocation
{

    NSString *insertStatement = [NSString stringWithFormat:@"INSERT INTO location (latitude, longitude, timeStamp) VALUES (%g, %g, %g)",newLocation.coordinate.latitude, newLocation.coordinate.longitude, newLocation.timestamp];    
    char *error;   
    if ( sqlite3_exec(databasehandle, [insertStatement UTF8String], NULL, NULL, &error) == SQLITE_OK)
    {
        NSLog(@"Location inserted. %g", newLocation.coordinate.latitude);
    }    

    else NSLog(@"Error: %s", error);
}

Answer 1

我解决了因为我要远程处理到minimac，所以数据库的文件路径被隐藏了。我只是将正确的文件路径粘贴到了文件夹中，然后找到了正确的文件。