Question

I have a copy of my db in Supporting Files folder. I need update a couple of tables and I am trying to use method to make writeable copy of db.

- (void) createEditableDatabase
{
   BOOL success; 
   NSFileManager *fileManager = [NSFileManager defaultManager]; 
   NSError *error;
   NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,NSUserDomainMask,YES);
   NSString *documentsDir = [paths objectAtIndex:0];
   NSString *writableDB = [documentsDir stringByAppendingPathComponent:@"yc_ch.db"];
   success = [fileManager fileExistsAtPath:writableDB];
   NSString *defaultPath = [[[NSBundle mainBundle]resourcePath]stringByAppendingPathComponent:@"yc_ch.db"]; 
   success = [fileManager copyItemAtPath:defaultPath toPath:writableDB error:&error];
   if (!success) 
   {
    NSAssert1(0, @"Failed to create writable database file:'%@'.", [error localizedDescription]);
   }
}

I have created (typed, physically) the ‘Documents’ folder in the root. At moment hierarchy of docs looks like this:

When I run my app. I am getting NSAssert1(0, @”Failed to create writable database file:’%@’.”, [error localizedDescription]);.

What’s wrong with it?

Answer 1

You copy the file even if the file already exists in the Document, I think NSFileManager copyFileAtPath: will return NO if file already exists at destination, hence failing your check and raising your NSAssert

success = [fileManager fileExistsAtPath:writableDB];
if (success)
{
    return;
}

So the file isn’t copied over if it already exists in your document. If that’s what causing the error, can you actually post the assertion, [error localizedDescription] will at least tell you what is wrong with it at the moment.

Edit:

- (void) createEditableDatabase
{
   BOOL success; 
   NSFileManager *fileManager = [NSFileManager defaultManager]; 
   NSError *error;
   NSString *writableDB = [[NSHomeDirectory() stringByAppendingPathComponent:@"Documents"] stringByAppendingPathComponent:@"yc_ch.db"];
   NSLog(@"Document path = %@", writableDB);
   success = [fileManager fileExistsAtPath:writableDB];
   if (success)
   {
       return;
   }
   NSString *defaultPath = [[NSBundle mainBundle] pathForResource:@"yc_ch" ofType:@"db"];
   NSLog(@"defaultPath = %@", defaultPath);
   error = nil;
   success = [fileManager copyItemAtPath:defaultPath toPath:writableDB error:&error];
   if (!success) 
   {
       NSAssert1(0, @"Failed to create writable database file:%@", [error localizedDescription]);
   }
   if (error)
   {
        NSLog(@"error = %@", [error localizedDescription]);
   }
}