| Then you might be even more surprised to find out that Foreign Data Wrappers are Postgres' implementation of the ANSI SQL standard extension known as "SQL/MED" [1], where MED stands for "management of external data". I spent a number of years working on a data federation/virtualization engine - and SQL/MED is very much related to that. It's actually a relatively unknown topic by many software/data engineers I have worked with, but things like GraphQL federation (example, Apollo GraphQL) or some of the more popular tools such as Presto, Dremio, Denodo, etc.) are where more advanced versions of this are today. SQL/MED and what Postgres can do is quite cool, but just know that any time you have system boundaries you cross (e.g. between heterogenous systems), things like joins, data types, and many other things becoming a bit more difficult - or you just have to think about them more. But very cool tech. I've used SQL/MED in Postgres, FDW, linked servers in SQL Server, database links in Oracle, and more advanced virtualization/federation engines also. If you haven't been exposed to this area before, highly recommended as another tool to know about for the toolkit. [1] https://en.wikipedia.org/wiki/SQL/MED |