60's tech
This is the reason that "object databases" have not caught on. They are just referential databases rebadged. Relational databases are better. Referential databases are a step back.
Note the comaprson with XML. Raw XML is hierarchical. XML with XPath and pointers is referential. It still hasn't caught up with the relational model, which has been around for years. That's why using XML to store bulk data sucks compared to doing it the Right Way and putting together an SQL database.