Hello, please tell me how best to build a structure. The question is rather logical, I don’t understand correctly yet. At the moment, the form to add a session at the cinema looks like this.

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Before that, I resolved other issues and considered that everything was fine for now, but now I understand that the structure is most likely not correct. At the moment, when you click on the "Create film session" button, one record is created in the database with the starting date of the movie rental in the cinema, and the final one. At this session you can book a place:

enter image description here

But this logic is not correct, because every day from the beginning of the movie rental in the cinema and until the end of the rental there should be a new (clean) session, with an appropriate date, which will allow users to book a place for the relevant day. And it turns out that when adding a new session, as in the first screenshot, not 1 entry should be added to the database, for example, 30 (from 1 to 30 numbers), and in each of them there is a different date. (This screenshot shows that the user should have possibility to book a place by choosing one of the available days) enter image description here The question arises, isn’t this a shit?) After all, if there are many sessions, there will be too many records in the database. And the second question is much more important: when creating a session (as in the first screenshot) there will still be a choice of time (9.00, 12.00, 14.00, etc.) using checkboxes. It turns out that, for example, for a session that goes into a rental on May 15, 2016, the time will be 10.00, 16.00, and 21.00, which will lead to 3 records in the database. And if such a film will go for 10 days at the box office, then there will be 300 records in the database immediately, and this is only for one movie. And if the films will be 5 or 10 ..) In general, please tell me how best to implement this, otherwise I do not have enough experience, and I encounter similar problems for the first time.

  • I didn’t work with Ruby, but I think your question is more about database organization. Look about the principles of a relativistic database . - Gleb Kemarsky

1 answer 1

No, everything is fine with the recording of the movie and the points of the beginning and end of the rental. It is good that the record is not duplicated and does not repeat the same information 30 times (which you need to demolish and insert again during editing).

Another thing is that under the reservation you need a separate table / model, where each entry corresponds to one booking fact (film, date, session / hour, cinema, seat in the hall). Moreover, the entire data set, firstly, must be unique on the one hand, i.e. on the other hand, do not go beyond the limits of the rental of the film, which you keep in the additional table / model.

I would implement these restrictions through validation at the model level. First, a unique validation of the set (film, day, session, cinema, place). Something like

validates :film_id, uniqueness: {scope: [:book_at, ... , :seat_id]}

Secondly, validation of the date in the selected interval, something like

 validates :book_at_in_intrval

Where book_at_in_intrval is a method for checking book_at_in_intrval is book_at_in_intrval in the rental interval.