Support PostgreSQL Table Inhertiance

[kiitosu]

Things to check first

• I have searched the existing issues and didn't find my bug already reported there

• I have checked that my bug is still present in the latest release

Sqlacodegen version

3.0.0rc5

SQLAlchemy version

2.0.29

RDBMS vendor

PostgreSQL

What happened?

When using sqlacodegen to generate ORM classes from an existing database schema, the child table ORM classes that inherit from base tables are not created. This issue occurs when there are tables using SQLAlchemy inheritance.

Is there any way to codegen child tables?

Database schema for reproducing the bug

Up migrateion to reproduce is like below.

create schema "test";

CREATE TABLE "test"."base" ("base" integer NOT NULL, PRIMARY KEY ("base") );COMMENT ON TABLE "test"."base" IS E'base';

CREATE TABLE test.sub (
    sub_data integer
) INHERITS (test.base);

Generated code.

# Using geoalchemy2 0.14.7
from sqlalchemy import Column, Integer, PrimaryKeyConstraint, Table
from sqlalchemy.orm import DeclarativeBase, Mapped, mapped_column

class Base(DeclarativeBase):
    pass


class Base(Base):
    __tablename__ = 'base'
    __table_args__ = (
        PrimaryKeyConstraint('base', name='base_pkey'),
        {'comment': 'base', 'schema': 'test'}
    )

    base: Mapped[int] = mapped_column(Integer, primary_key=True)


t_sub = Table(
    'sub', Base.metadata,
    Column('base', Integer, nullable=False),
    Column('sub_data', Integer),
    schema='test'
)

[agronholm]

Please provide a sample schema and the code generated from it.

[kiitosu]

@agronholm
Thank you for your replay.
I added information, please check it!

[agronholm]

OK, so by "SQLAlchemy inheritance" you really meant PostgreSQL inheritance. The two are totally different concepts. SQLACodegen has never been tested against PostgreSQL inheritance, and I don't think SQLAlchemy's reflection can even detect that, and as a consequence, SQLACodegen would not know about it either.

[kiitosu]

@agronholm
Thank you for the explanation. Indeed, it is PostgreSQL inheritance. So, it's not a bug, is it? Is it possible to make a feature request? Would it be necessary to consult with SQLAlchemy first since their support is required?

[agronholm]

Check with upstream SQLAlchemy first. The use of database-side inheritance is not a common usage pattern.