I have been programming in PHP for several years and have, in the past, adopted methods of my own to handle data within my applications.

I have built my own MVC, in the past, and have a reasonable understanding of OOP within php but I know my implementation needs some serious work.

In the past I have used an is-a relationship between a model and a database table. I now know after doing some research that this is not really the best way forward. As far as I understand it I should create models that don't really care about the underlying database (or whatever storage mechanism is to be used) but only care about their actions and their data.

From this I have established that I can create models of lets say for example a Person an this person object could have some Children (human children) that are also Person objects held in an array (with addPerson and removePerson methods, accepting a Person object).

I could then create a PersonMapper that I could use to get a Person with a specific 'id', or to save a Person.

This could then lookup the relationship data in a lookup table and create the associated child objects for the Person that has been requested (if there are any) and likewise save the data in the lookup table on the save command.

This is now pushing the limits to my knowledge.....

What if I wanted to model a building with different levels and different rooms within those levels? What if I wanted to place some items in those rooms?

Would I create a class for building, level, room and item

with the following structure.

building can have 1 or many level objects held in an array level can have 1 or many room objects held in an array room can have 1 or many item objects held in an array

and mappers for each class with higher level mappers using the child mappers to populate the arrays (either on request of the top level object or lazy load on request)

This seems to tightly couple the different objects albeit in one direction (ie. a floor does not need to be in a building but a building can have levels)

Is this the correct way to go about things?

Within the view I am wanting to show a building with an option to select a level and then show the level with an option to select a room etc.. but I may also want to show a tree like structure of items in the building and what level and room they are in.

I hope this makes sense. I am just struggling with the concept of nesting objects within each other when the general concept of oop seems to be to separate things.

If someone can help it would be really useful.

Many thanks