IFC Modernization : Relationships

I’m not a programmer, but because of our existing startup I have to learn the existing solution as much as I can, at least general things

So, as I know generally, if a data structure has a “structured form” it’s better use “relational databases” --> SQL
If the data structure is “complex and unstructured” form then is better use “Object-Oriented database”

So, the IFC data structure is complex? Unstructured?
If not, why was it originally developed based on Object-Oriented approach?

So I think “SQL” would be a better choice for schema (It’s fast, has better performance, is clear and doesn’t cause headache and lot of mistakes, etc)

But all “information systems” would be “Object-Relational Systems” which have a “Relational database” and “Object-Oriented frameworks”

http://www.cis.umassd.edu/~jbergandy/process/workflow/ana_desi/co_rdbom.htm