[DISCUSS] Improvements to the Unified SQL Connector API

[Timo Walther]

Hi everyone,

as some of you might have noticed, in the last two releases we aimed to 
unify SQL connectors and make them more modular. The first connectors 
and formats have been implemented and are usable via the SQL Client and 
Java/Scala/SQL APIs.

However, after writing more connectors/example programs and talking to 
users, there are still a couple of improvements that should be applied 
to unified SQL connector API.

I wrote a design document [1] that discusses limitations that I have 
observed and consideres feedback that I have collected over the last 
months. I don't know whether we will implement all of these 
improvements, but it would be great to get feedback for a satisfactory 
API and for future priorization.

The general goal should be to connect to external systems as convenient 
and type-safe as possible. Any feedback is highly appreciated.

Thanks,

Timo

[1] 
https://docs.google.com/document/d/1Yaxp1UJUFW-peGLt8EIidwKIZEWrrA-pznWLuvaH39Y/edit?usp=sharing