sqlalchemy-postgres-point 0.1.0

Lightweight SQLAlchemy custom type for PostgreSQL POINT columns with tuple binding and an earth-distance comparator.

sqlalchemy-postgres-point

Lightweight, pure-Python SQLAlchemy custom type for PostgreSQL POINT columns.

Why

PostgreSQL has a native POINT type (stored internally as a pair of float8 values). SQLAlchemy does not ship a dedicated high-level type wrapper for simple geometric primitives. This package provides a very small PointType you can use immediately without pulling in a full spatial stack (e.g. PostGIS + GeoAlchemy2) when all you need is storing and retrieving (longitude, latitude) pairs.

Features

• Simple (lng, lat) tuple binding and result conversion.
• Safe NULL handling.
• Literal rendering for DDL / SQL emission.
• Custom comparator exposing the PostgreSQL earth-distance <@> operator (returns a Float).
• cache_ok = True for SQLAlchemy 2.x compilation caching.

Installation

Using uv (recommended):

uv add sqlalchemy-postgres-point

Or with pip:

pip install sqlalchemy-postgres-point

Usage

from sqlalchemy import Column, Integer
from sqlalchemy.orm import DeclarativeBase
from sqlalchemy_postgres_point import PointType


class Base(DeclarativeBase):
	pass


class Place(Base):
    __tablename__ = "places"
    id = Column(Integer, primary_key=True)
    # Store as (longitude, latitude)
    location = Column(PointType)

# Example query using the custom comparator
from sqlalchemy import select

origin = (0.0, 0.0)
stmt = select(Place.id, Place.location.earth_distance(origin).label("dist"))

The comparator translates Place.location.earth_distance(origin) into SQL using the <@> operator (requires PostgreSQL with the cube / earthdistance extension for meaningful results; without extensions the operator may not exist—adapt as needed for your environment). This library only emits the operator; it does not manage PostgreSQL extensions.

Returned Python Values

Values are loaded as a 2-tuple of floats (lng, lat) or None when NULL.

Testing

Run the test suite with:

uv run pytest -q

Development

After cloning:

uv sync  # installs runtime + dev deps
uv run pytest -q

Project Structure

• sqlalchemy_postgres_point/point.py – Implementation of PointType.
• tests/test_point.py – Unit tests for processors and comparator.

Limitations / Notes

• No automatic validation of longitude/latitude ranges; add your own if required.
• Uses simple textual representation (lng,lat) accepted by PostgreSQL POINT input parser.
• If you need advanced spatial indexing / SRID support, look at GeoAlchemy2/PostGIS instead.

License

MIT (see your project's LICENSE file if added later). Contributions welcome.