From observation over the years, one that has supports/can use a gui interface that a newbie can use to build things (postgress, sqlite, libreoffice) without need to have coding/db coding knowledge. Ideally, one that has support for what's being used to build the web app (aka .net, python, ruby, etc), forms/reports, etc.

IMHO, pre-built/ready made content relation management tool (crm) would seem to match what's been stated.

For just straight up dumping contacts in a table without considering data/security issues:

   a) https://www.postgresql.org/about/news/announcing-sqlpage-build-dynamic-web-applications-in-sql-2672/

   b) https://execsql.readthedocs.io/en/latest/ 

   c) https://www.gnu.org/software/recutils/manual/html_node/index.html

      tutorial : https://gist.github.com/gmolveau/6be062d9b9005cf985cda98dabdf0baa

      https://www.youtube.com/watch?app=desktop&v=A1whwi-Gc0Y

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Misc postgres gui tools : https://wiki.postgresql.org/wiki/Community_Guide_to_PostgreS...