1 Attachment(s)
Entity relationship diagrams
Hi everyone, long time no see :wave:
I am working on a small project which consists of making a system for a leisure center using visual basic. At the moment i am working towards my investigation and design, i am little bit stuck and need some advice from anyone of you who know a little bit about Entity relationship diagrams.
In the project i am working on i am have to design and build a system which could allow sports hall, personal trainer, different type of classes e.g dance classes bookings. A member can sign in after he registers with the centre and start booking different type of facilities. Moreover, the there are many people working in the centre, like receptionists, class instructors and personal trainers.
I have design an ERD for this. I just need know if i am correct or need some modifications in my design.
Attachment 162615
Have small brief:
- A member can have many PT sessins and class bookings
- A member can also have many Sports hall bookings
- One personal trainer can be booked more than once
- A class instructor can be booked more than once
So what do you think? Am I missing something here or is everything fine?
Cheers
Re: Entity relationship diagrams
I'll be honest... something doesn't feel right about it... but I don't know that I can pin point or articulate what it is. Call it gut instinct.
Actually, I think what I'd do is reduce the number of entities...
Member, Booking, Staff ... Member and Staff should be self-evident as to what they are. Booking then would have a Type that would indicate if it's a Class, PT, or Sports Hall .... All bookings should be pretty much the same, they are going to have a title, a start time, end time, 0 or more instructors, and 1 or more members, and maybe a few more bits of information.
Be careful how you actually build your classes though... don't build them in a way that will allow for endless chaining... where you go Member.Bookings(0).Members(0).Bookings(1).Staff(0).Bookings(0)..... and so on... I've seen it done and it will create rabbit holes you really don't want to follow.
-tg
