Im in need of some help. Most of all in the way i think when creating the ERD. I have searched online and asked some people but i think i formulate my question wrong which in turn confuses people. (sorry for the bad english btw)

My school gave me an assignment to create a ERD regarding a cinema and their members. What i am struggling most with is to create the relationships between the entities.

As u can see i have "a member visits 1 movie". But is it wrong of me to think that a member can visit multiple movie? Like not at the same time ofcourse but at different times. So like a member can visit 0 or many movies in his lifetime (or the day/week). This is the same issue i have regarding movie`s and cinemas.

In my ERD "a movie plays in 1 room and a room plays 1 movie" but is it not possible that a movie can play at multiple rooms? and a room can play multiple movies throughout the day?

Is this dependend on the entity "schedule"? And should i place my schedule entity between movie, cinema room and employee? Would it make more sense that way? Is what i am asking possible in both ways? And should i ask these questions to the one that gave me this assigment since the decide how they want a database?

Alot of questions. I have looked at multiple example ERD`s and it only confuses me more.

PS : Apologies regarding the english and also dont look at the membership entity. A member has the option to purchase more then 1 membership according to the assignment.

ERD Cinema

  • 1
    "is it wrong of me to think that a member can visit multiple movie?" -- No, it's not wrong. Adjust your design accordingly. – mustaccio Oct 30 '19 at 22:50
  • Have a look at the two answers here - database schema design is, in essence, an iterative process. I don't know what your development environment is, but start with your basic schema, try and run code against it, find the bugs (there will be bugs!) and then tweak/redesign your schema. Search [here]databaseanswers.org/data_models/index.htm) for the word "cinema" - you may find that schema helpful. Also, search for open source cinema booking software - I found a few links which might be of interest. – Vérace Oct 31 '19 at 12:35
  • Mustaccio and Verace, Thanks for both answers. Im not into DB/SQL so this helps me out. I only have to design the ERD. But not really put it into SQL. Thanks for the answers. im gonna try the links. – romano Schees Oct 31 '19 at 16:39

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