schnittmengen in db abbilden

[schildi]

ich habe das momentan etwa so gelöst (hier nur pk's bzw. zusammengesetzte pk's oder fk's hingeschr.):
(isin == fund_id)

funds [isin, [...]]
options [option_id, [...]]

fund_option_availability [option_id, isin, [...]]

fund_companies [company_id, [...]]
fund_platforms [platform_id, [...]]

fund_platform_fund_availability [platform_id, isin]
fund_company_fund_availability [company_id, isin]

fund_company_option_availability [company_id, option_id, isin]
fund_platform_option_availability [platform_id, option_id, isin]