Creating User Generated Models and SQL Tables in Ruby on Rails 4

Question

Considering scenario of an Inventory Management System. Inventory has many types of items, each with own table and columns. One, two or Twelve tables are not sufficient to describe the plethora of the TYPES of items as they are extremely varying. e.g. some attributes of a family of items like BIKES do not have the same attributes of CARS. It is tedious for developer to take into account the thousands of the TYPES of items and incorporate them into each model manually.

Is there a way for users to generate models themselves? thereby generating own SQL tables etc... Is there another approach to this problem? (Maybe using Semantic Web Technologies)

Coming from Spring Framework, I am fairly new to RoR development.

Thanks in Advance.

Answer 1

I'm not an expert, but you could do it with regular, pre-defined models.

• Item_Type
• Item_Attribute
• Item

Item_Type would have a name variable (not unique), and perhaps any other common attributes you'd want. It would then have a has_many Item_Attributes relationship, whereas Item_Attribute belongs_to Item_Type.

So I'd make a view that allows the user to add new Item_Types and then define Item_Attributes for those item types.

Then you could have the actual Item model, each instance of which is the existence of an Item_Type in the inventory. Item belongs to Item_Type, and Item_Type has_many Items, and Item cannot have a null Item_Type.

So a user creates a new Item_Type with the name "BIKE", then adds several Item_Attributes to it, such as "Mountain" and "Red". Then the user can create a new Item that has a relationship to the "BIKE" Item_Type.

If they wanted to add a blue mountain bike instead of a red one, they would need to go through the process again, adding another Item_Type of "BIKE" except adding "Blue" as an attribute for the new instance of Item_Type's Item_Attributes.