How do I find an unknown flight reservation number?

I have lost my flight reservation number. I think it’s for frontier airlines. All I have is the dates I reserved. I don’t know which site I used to book it.

air travel – Changing EasyJet reservation: what happens to my Extra Legroom surcharge?

On EasyJet, to bring a personal item on board in addition to a cabin bag, I had to select an Up Front or Extra Legroom seat (with a surcharge).

If I change my reservation to another flight, will I have to pay the surcharge again to select an Up Front or Extra Legroom seat on the new flight? If so, will the surcharge from the original flight be refunded?

What’s the closest experience to Yosemite if you cannot get a reservation?

Yosemite still requires reservations even to drive through it, through September 30, due to Covid.

Is there a way to see some of Yosemite without going inside it?

bookings – Extending Domestic Reservation in the US

Suppose a passenger is in the USA and has booked a round trip reservation leaving from New York City to Miami. Here are some notes:

  1. He is leaving New York City on July 5.
  2. He is coming back from Miami on July 8.

If he wants to extend this trip to July 14, what would be the additional cost he would have to pay to make this change?

product – Stock reservation being dubled

I have tons of products but one of them, when a customer does order and it’s pending, it reserves 2 times the units.
But it only happens on that one product, a customer made a 10unit order and now I have negative stock because it’s reserving 20units for some reason.
I don’t know if it matters but it was a simple product and now it’s inside a configurable, the other options in that configurable work just fine.

What can be the reason for this?

air travel – Cheapest Air India Reservation Tickets

Get Air India baggage policy and solve your questions. Abundance Baggage Rates are given in USD and thus rates would be relevant in USD or its comparable in neighborhood cash. GST rates will be material on the worth considered all Excess Baggage tickets (EBTs), gave in India, aside from the absolved air terminals.

Schengen visa reservation of return flight from another country than accommodation

I am going for travel from Barcelona (which is my main destination) and will continue to Amsterdam. Instead of booking my return flight from Amsterdam, the travel agency booked my return flight from Barcelona.

My accommodation papers show that I was in Amsterdam 1-2 days before the return flight. After I told him that I am getting back from Amsterdam, he said it doesn’t matter there is train (which makes the story that I did go from Barcelona to Amsterdam, and then from Amsterdam back to Barcelona for my return trip).

Do they actually care about this a the embassy? Can my visa get rejected because of this?

mysql – Hotel Reservation Database design problems

I’m working on a simple database for a college project. I am pretty much a beginner in this field, as you might have guessed. For my database, I put together the following ER diagram and Schema diagram, I’d appreciate it if you could point out any issues.

The idea is that We have a hotel chain that operates some hotels, and then someone sits behind the software and adds bookings for each hotel. Each Hotel has some rooms and each room belongs to a room type. Guests can use the services provided by each hotel and the cost of that service should be added to their total cost. I don’t think the current state of rooms, room_type, rooms_booked and bookings table is correct.

I want to get appropriate answers for the following queries:

  1. Show the guest that provided the most profit to the hotel chain.
  2. The most frequently used rooms.
  3. Cities that provided the most profit to the hotel-chain.
  4. Hotels that have been used more than others.
  5. List the services used by guests staying in smoke-friendly rooms.
  6. A list of hotels in a guests favorite city where the guest hasn’t yet checked in.

I’m not sure if the current design can address these queries at least not all of them.

  1. What changes must I make in order to work with design?
  2. I think in the current design, I am just saving all the current and past bookings made in one table, it just doesn’t make any sense.
    I am having difficulties designing this database and writing queries.

I uploaded the current design to

It can be edited when needed.

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tickets – On which trains in Japan is reservation mandatory?

First a reminder: whether one posseses a rail pass such as the Japan Rail Pass has no effect on seat reservation requirements. If reservation is required, it remains so if you have a rail pass. Of course, a rail pass usually allows you to make reservations free of charge, but it is still necessary to visit the ticket office to make your reservation. (Note that some minor regional passes do not allow you to make reservations; in that case all-reserved trains require payment of at least the reservation fee.)

Firstly, there are four all-reserved Shinkansen services. Note that all services on the Tokaido-Sanyo-Kyushu Shinkansen between Tokyo and Kagoshima-Chuo, serving Nagoya, Kyoto, Osaka, Hiroshima, Fukuoka, Kumamoto, etc. have non-reserved seats.

  • The Hayate and Hayabusa services on the Tohoku-Hokkaido Shinkansen between Tokyo and Shin-Hakodate-Hokuto. However, if your trip is fully on the section between Morioka and Shin-Hakodate-Hokuto, see the note at the bottom.
  • The Komachi services on the Akita Shinkansen between Tokyo and Akita. However, if your trip is fully on the section between Morioka and Akita, see the note at the bottom.
  • The Kagayaki services on the Hokuriku Shinkansen between Tokyo and Kanazawa.

If you try to make a reservation on one of those trains and the train is fully booked, you will have the option to obtain a standing ticket, which as its name implies lets you ride the train by standing in the intervals between carriages. A standing ticket is slightly cheaper than a reserved seat ticket, as it does not include the seat reservation fee. It is not possible to obtain a standing ticket in any other circumstance, such as if the train is not fully booked (in order to save money) or on any train other than the four above.

The two “premium” express services serving Narita airport are also all-reserved:

  • The JR Narita Express, serving many stations in the greater Tokyo area. However, see the note at the bottom.
  • The Keisei Skyliner, serving Nippori and Ueno.

The two surviving regularly scheduled overnight trains:

  • The Sunrise Seto, between Tokyo and Takamatsu.
  • The Sunrise Izumo, between Tokyo and Izumoshi.

Finally, almost all “touristy” trains are all-reserved, such as:

The easiest way to find out whether a given train has unreserved seats (or, in general, which seating options are available on it) is to look it up on Hyperdia, and see what options are available in the drop-down list of the “Seat Fee” column. If the column is empty, it means the train is an ordinary commuter train, where reservation is not possible in the first place.

Note about the Hayabusa, Hayate and Komachi services beyond Morioka. To compensate for the fact that no services with non-reserved seats exist beyond Morioka, it is possible to board those services without a reservation, by purchasing a “special limited express ticket” (特定特急券) instead of a regular reserved-seat limited express ticket. A special limited express ticket works in essentially the same way as a non-reserved-seat one would: it is cheaper than a reserved-seat one since it does not include a seat reservation fee, and it allows the holder to use any vacant seat, with the caveat that if another passenger has a reserved-seat ticket for that seat, the latter has priority. Rail pass holders, meanwhile, can simply board with just their pass.

Note about the Narita Express. Similarly, the Narita Express can be boarded without a reservation, by purchasing a “non-designated seat ticket” (座席未指定券) instead of a regular reserved-seat limited express ticket (or just boarding with a rail pass). As above, a non-designated seat ticket allows the holder to use any vacant seat, with the caveat that reserved-seat ticket holders have priority. However, a non-designated seat ticket costs the same as a reserved-seat one. A non-designated seat ticket can also be converted to a reserved-seat one at no extra cost.

architecture – How to avoid race condition in reservation system

I’m trying to design a system to buy mangoes (not really mangoes, but it’s a good proxy). One mango is the same as the other. These are very high-in-demand mangoes; quite possible many people at once will try to get a mango and there is a fixed amount of inventory.

Users will reserve a mango first, securing it for them to purchase and then if they don’t buy it within 10 minutes, the reservation is cancelled and that mango can be purchased by someone else.

Here’s where I see a race condition, and I am not sure how to best avoid it:

  1. Customer requests to reserve a mango
  2. Check inventory exists via inventory API (remaining inventory – reservations)
  3. Sufficient inventory
  4. Request reservation via reservation API. API starts to create reservation.
  5. User 2 calls inventory API and finds there is enough mangoes left
  6. User 2 calls reservation API. API starts to create reservation.
  7. User 1 reservation is complete. They reserved the last mango
  8. User 2 reservation is complete. They also reserved the last mango.

I really want to avoid this scenario:
With both users having successfully reserved the last mango, user 2 buys the mango, leaving user 1 with an error message when they try to buy.

Oh and my mango system is distributed, so multiple different instances running.

I’ve searched up and down Google and surprisingly can’t find an answer on preventing race conditions in inventory systems other than locking the DB. Is this really the best approach?