halfORM

⚠️ BREAKING CHANGES in v1.0.0

ho_get() is now public and returns a dict directly. It raises NotFoundError (0 rows) or MultipleRowsError (> 1 row) instead of counting first.

Deprecated query-builder setters removed — ho_limit, ho_offset, ho_order_by, ho_distinct no longer exist as setters. Pass these as keyword arguments to ho_select():
# Before (0.x)
rel.ho_limit = 10
rel.ho_order_by = 'name'
list(rel)

# After (1.0)
list(rel.ho_select(limit=10, order_by='name'))
FKEYS_PROPERTIES / FKEYS class attributes removed — use Fkeys only.

ho_cast() now raises CastError if the target is not in the PostgreSQL inheritance hierarchy of the relation.

See CHANGELOG.md for the full list of changes.

halfORM is a database-first ORM for PostgreSQL. Your schema lives in the database; halfORM introspects it at runtime and gives you Python objects to work with your data. No migrations, no code generation.

The central idea: a Relation object is a predicate. It describes the logical condition that rows must satisfy to belong to the relation. Its extension — the set of rows currently satisfying the predicate in the database — is what you read, update, or delete.

Key features

Database-first — the schema lives in PostgreSQL, not in Python classes.
Predicate model — relations are predicates; set operators (|, &, -) compose them before any SQL is sent.
FK navigation — join across tables (and views) by setting FK attributes; explicit Fkeys dict for views where PostgreSQL stores no FK metadata.
Sync + async — every executor has an a-prefixed async counterpart (ho_aselect, ho_ainsert, …).
Bulk load — ho_copy / ho_acopy for high-throughput inserts via PostgreSQL COPY.
No magic — queries are built from the predicate you describe and executed only when you call an executor. ho_mogrify() shows the exact SQL.

Install

pip install half_orm

Requires psycopg 3 (psycopg[binary]).

Configure

# ~/.half_orm/blog
[database]
name     = blog
user     = alice
password = secret
host     = localhost

Usage

from half_orm.model import Model
from half_orm.relation_errors import NotFoundError, MultipleRowsError

blog   = Model('blog')
Post   = blog.get_relation_class('blog.post')
Author = blog.get_relation_class('blog.author')

# Insert — returns the inserted row as a dict
alice = Author(
    first_name='Alice', last_name='Martin', email='alice@example.com'
).ho_insert()

# Query — Author(last_name='Martin') is a predicate, not a query
for row in Author(last_name='Martin').ho_select('id', 'email'):
    print(row)

# Get exactly one row
try:
    author = Author(last_name='Martin').ho_get()
except NotFoundError:
    print("no such author")
except MultipleRowsError:
    print("ambiguous — more than one author named Martin")

# FK navigation — no JOIN written by hand
post = Post(id=1)
post.author_fk.set()                         # join all authors
for row in post.ho_select(json_agg={'author_fk': ['first_name', 'last_name']}):
    print(row['author_fk'])                  # {'first_name': 'Alice', 'last_name': 'Martin'}

# Set operators — compose predicates before hitting the database
recent   = Post(created_at=('>', '2024-01-01'))
featured = Post(featured=True)
combined = recent | featured                 # UNION
print(combined.ho_count())

# Update / delete
Author(id=alice['id']).ho_update(email='alice@newdomain.com')
Author(id=alice['id']).ho_delete()

Documentation

Extensions

Extension	Description
half-orm-dev	Development tools — `half_orm dev` project scaffolding, patch management, and schema synchronisation.

License

halfORM is licensed under the GPL-3.0 license.

Metadata

Release files for half-orm 1.0.0rc18

For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.

Source distribution (sdist)

Source distribution for half-orm 1.0.0rc18
File	Size	Uploaded	Provenance
half_orm-1.0.0rc18.tar.gz	83.5 kB	Sep 3, 2026	Without provenance	Details

Built distribution (wheel)

Table of built distributions (wheels) for half-orm 1.0.0rc18
File	Interpreter	ABI	Platform	Reset
half_orm-1.0.0rc18-py3-none-any.whl 79.7 kB Sep 3, 2026 Without provenance	Python 3	none	any	Details

Total release size: 163.2 kB

Release files / half_orm-1.0.0rc18.tar.gz

Download URL	half_orm-1.0.0rc18.tar.gz
Size	83.5 kB
Tags	Source
SHA-256 checksum How to use checksums	`6fc975a8d2842dde567578aa10bb04a7f494f9f17882100735e234c88ba2959a`
BLAKE2b-256 checksum How to use checksums	`137a5c5fb0afea20113ecb7af4138d556eaad0377ee7f7fef0d943520e520c88`
Upload date	Sep 3, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	No
Uploaded via	`twine/6.2.0 CPython/3.14.6`

Release files / half_orm-1.0.0rc18-py3-none-any.whl

Download URL	half_orm-1.0.0rc18-py3-none-any.whl
Size	79.7 kB
Tags	Python 3
SHA-256 checksum How to use checksums	`3d209897440a1850def36035d986e66857fa020f63081fc844393d98e687410f`
BLAKE2b-256 checksum How to use checksums	`6c8ffacb55f12dc50c11459941e5ba66c22f07f8e6a95cb6fddc3577a67c320f`
Upload date	Sep 3, 2026
Uploaded using Trusted Publishing? What is trusted publishing?	No
Uploaded via	`twine/6.2.0 CPython/3.14.6`

Security for half-orm 1.0.0rc18

Report project as malware

Provenance

Provenance describes where a file came from. On PyPI, provenance is shared via attestations, which provide a verifiable record of the build or publishing details. View details, limitations and caveats.

No provenance found

None of the files in this release were uploaded with provenance metadata.

A note on package security

PyPI is a repository for distributing packages, not a service for auditing them. While third-party security researchers and our staff do their best to detect and remove malicious packages, PyPI cannot guarantee the quality, security or suitability of any given package.

To learn more about protecting yourself from malicious actors, visit our package security documentation.