crash:setObjectForKey: object cannot be nil

[1257331501]

            case SQLITE_TEXT:
            {
                const char *value = (const char*)sqlite3_column_text(statement, i);
                [result setObject:[NSString stringWithCString:value encoding:NSUTF8StringEncoding] forKey:columnName];
                break
          }

value 为nil 或者 [NSString stringWithCString:value encoding:NSUTF8StringEncoding] 这个为nil 造成的。
是不是要改成这样
NSString *valueString = [NSString stringWithCString:value encoding:NSUTF8StringEncoding] ?: @""
[result setObject:valueString forKey:columnName];