httk.store.backend.postgresql.engine
====================================

.. py:module:: httk.store.backend.postgresql.engine

.. autoapi-nested-parse::

   PostgreSQL database construction for :class:`~httk.store.backend.sql.engine.Backend`.



Functions
---------

.. autoapisummary::

   httk.store.backend.postgresql.engine.database


Module Contents
---------------

.. py:function:: database(cls, url, *, database = None)

   Build a PostgreSQL-backed backend from a ``postgresql://`` URL.

   PostgreSQL is fully transactional and rides the existing ``"transactional"``
   write profile with no special-casing. Only the psycopg 3 driver is
   supported: a bare ``postgresql://`` URL is normalized to
   ``postgresql+psycopg://`` (SQLAlchemy 2.0 would otherwise select psycopg2),
   and any other explicit driver is rejected.

   :param cls: The backend class to instantiate.
   :param url: PostgreSQL SQLAlchemy URL or URL string.
   :param database: The database name overriding the URL path, if supplied.
   :return: The configured PostgreSQL backend wrapper.
   :raises ImportError: If ``psycopg`` (psycopg 3) is not installed; install the
       ``httk-store[postgresql]`` extra to use ``Backend.postgresql()``.
   :raises ValueError: If the URL names a driver other than
       ``postgresql+psycopg`` (psycopg 3).