model-dml 0.0.4

A package for SQLAlchemy models DML mixins.

model_dml

A package for SQLAlchemy models DML mixins.

Features

• Three methods for DML operations: insert, update, delete.
• Add those methods to models through mixin classes.
• Support returning selected columns for all methods.

Installation

pip install model_dml

Usage

Custom Base

To use model_dml, you need to create a custom base class for your models with a session_maker method.

What is a sessionmaker:

• Using a sessionmaker
• sessionmaker documentation and example

class Base(sqlalchemy.orm.DeclarativeBase):
    @classmethod
    def session_maker(cls) -> sqlalchemy.orm.sessionmaker:
        return <Namespace>.Session

This method exist to allow DML methods to access the sessionmaker without creating a new reference that would also need to be monkey patched. By returning the sessionmaker from the namespace, only <Namespace>.Session needs to be monkey patched.

Compose your model with what you need

class User(base, model_dml.Insert, model_dml.Update, model_dml.Delete):
    __tablename__ = "users"
    id: sqlalchemy.orm.Mapped[int] = sqlalchemy.orm.mapped_column(primary_key=True)
    name: sqlalchemy.orm.Mapped[str] = sqlalchemy.orm.mapped_column(sqlalchemy.String(30))

You can use model_dml.DML which is a helper class that composes all the mixins together.

class User(base, model_dml.DML):
    __tablename__ = "users"
    id: sqlalchemy.orm.Mapped[int] = sqlalchemy.orm.mapped_column(primary_key=True)
    name: sqlalchemy.orm.Mapped[str] = sqlalchemy.orm.mapped_column(sqlalchemy.String(30))

Use the DML methods

User.insert(dict(name="John"))
User.insert({'name': "Jane"})
user = User.insert({'name': "Jack"}, returning=[User.id, User.name])