Hi all!

I am designing a DB for a company that sells industrial equipment.

The problem is that those equipments are quite complex and can be quite customised. Up to now I have the following tables:

EQUIPMENT: holding technical data
PART: where all parts and assemblies are
ASSEMBLY: linking rows in PART to build assemblies. An ASSEMBLY can be made up of parts and assemblies.

Every row in EQUIPMENT is linked to one or more rows in PART
Rows in PART can occur in many rows in EQUIPMENT

-First problem is that many assemblies might have options (an option can be an assembly or a single part) and that sometimes there are alternatives for an option. For example: the assembly 'Engine' (made up many parts and assemblies) might have an 'Engine Starter' which is EITHER electrical or pneumatical. The 'Electrical engine starter' is in turn made up parts and assemblies.

-Second problem: I should keep track of the equipment sold by the employees of my company. Not only which equipment was sold, but also which options. The configuration of the assemblies changes relatively seldom. But it changes!

It would be great if someone could assist me with these issues.
Thank you very much for your comments!