Question

I’m having hard time with this project, I’m building a boat configurator which is divided in categories / packages / extras.

Each category is disconnected with the other, so it’s not a big problem.

The problem comes out with packages and extras. Extras are options that can be chosen within a package (increasing the total price). I’ll explain all dependencies that can exists between these 2 objects:

1. There are times where you can also purchase a package all toghether, which could have an extra (or 2) that are upgrades to that package
2. There are times where you can buy a single package between 4-5 and additionally you can buy some extras in another 6th package
3. Sometimes an extra can be bought only if you have at least one item in a given package
4. Sometimes an extra can be bought only if you have a specific extra

At the moment I don’t have any other dependency in my mind (but I’m sure there are others possible).

I don’t know which approach I should take to store all this dependencies, I have 3 basic sql tables (category, package, extra which are not connected because a Package => Extra dependency could be different for other categories) and CategoryRelationship, PackageRelationship, ExtraRelationship but I’m having hard time in express some dependencies, expecially the 2nd which is not limited to a single id field.

How is normally handled all these interdependencies?

I never faced this problem, thanks for any suggestion

Edit 1:

I’m thinking about changing the approach to 1 Table for each “type” of dependency, can it be considered a good way to handle instead of a single table with all type of dependencies?

Answer 1

Because no one answered this, I’m posting the approach I finally used for this project and which I find interesting.

I created 1 table for each type of dependency (as I told in Edit 1). Each table can have multiple reference to an item of any id and is possible in this way to organize quite well all columns that represents dependencies.

The approach is inspired by CakePHP Validation model, where each validation is a class that has a validate method which will be run.

Hopefully this will help someone else; I’ll mark this as answer if no one provide an answer with a better suggestion.