develop database for ecommerce website

Question

we have scenario.. where need to develop database for ecommerce website. having products with different category and attributes.. like electronics, footwear, fashions, etc.. we choose mongodb (NoSql).. it is quite easy but we don't have Joins.. if we go with relational db .. products with parent child tables .. leading headache to structure it.. and leads in slow at retrieval. Please help with that..