Using SQL databases (MySQL, PostgreSQL, others) in Plone
If you are building the codebase Plone behaves as any other Python application.
Write your SQL related code using known available Python SQL libraries and frameworks
Plug your code to Plone HTML pages through views
Example Python SQL libraries
ZSQL is something probably written before you knew what SQL is. Never ever use ZSQL in new code. It’s not following any modern best practices and has history of 1990s code. You have been warned. Stay away. The grue is near.