ios - 在 Objective-C 中检查数据库中空字符串的正确方法是什么

Question

我想在数据库中行中没有数据时限制数据库而不是无法显示异常我只是想限制空值

  if ([[Utility checkNullValues:tInfo.product_price]isEqualToString:@""]) {
        [Utility showAlertView:@"Sorry" message:@"No Product You Buy." viewcontroller:self];
      }

这就是错误:

2015-06-03 12:35:38.320 NiColi[28363:2438247] * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '* +[NSString stringWithUTF8String:]: NULL cString' *** First throw call stack:

Answer 1

NSString *str = ((char *)sqlite3_column_text(compiledStatement, 1)) ? [NSString stringWithUTF8String:(char *)sqlite3_column_text(compiledStatement, 1)] : nil;