NSFileManager

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectoryPath = [paths objectAtIndex:0];
NSString *secondaryDirectoryPath = [documentsDirectoryPath stringByAppendingPathComponent:@"secondary"];
NSString *databaseFile = [secondaryDirectoryPath stringByAppendingPathComponent:@"database.db"];

NSFileManager *fileManager = [NSFileManager defaultManager];
[fileManager removeItemAtPath:databaseFile error:NULL];

UIWebView disable scrolling

1. objc
UIWebView *webView = [[UIWebView alloc] initWithFrame:CGRectMake(0,0,320,480)];
[[[webView subviews] lastObject] setScrollEnabled:NO];

2. javascript
document.onload = function(){
    document.ontouchmove = function(e){ e.preventDefault(); }
};