Iphone – When to release NSUrlConnection object

As epatel said, you don't need to release that particular string. If you wanted to be more proactive, you could do this instead:

-(NSMutableArray *) getPaises {
    NSMutableArray * paises;
    paises = [[[NSMutableArray alloc] init] autorelease];
    while( get new row ) {
        NSString *aPais =  [[NSString alloc] initWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 0)];
        [paises addObject:aPais];
        [aPais release];
    }
    return paises;
}

In summary:

• [[NSString alloc] initWith...] -> You must release or autorelease.

• [NSString stringWith...] -> No need to release.

-- Edit: Added autorelease for paises, as you are returning it. When you return an object, always autorelease it if you have alloc&init'd it.

A couple of things stick out. For example within the URLDownload class the call to [request release] will never be reached as its placed after the return statement

return [request urlData];
[request release];