pg.el
This module lets you access the PostgreSQL object-relational DBMS from Emacs, using its socket-level frontend/backend protocol. The module is capable of automatic type coercions from a range of SQL types to the equivalent Emacs Lisp type. This is a low level API, and won't be useful to end users.
Should work with Emacs version 24 or newer and Postgres 9 or newer. The module only supports version 3 of the protocol with md5 or scram-sha-256 based password authentication.