PostgreSQL, connected in place.

Your orders database runs on PostgreSQL and holds the order system: customers, orders, deliveries and invoices for three legal entities. WhoDB connects to it where it runs, labels what is inside in plain business terms, and lets apps use it alongside every other source.

From tables to business entities.

select o.order_no, c.name, o.total_gross
from sales_order o
join customer c on c.id = o.customer_id
where o.state = 'locked'
  and o.promise_dt < current_date;

Queries run on PostgreSQL with the permissions you granted. Results come back as rows in WhoDB and can be saved as a dataset, joined with other sources, or used by a function.