aio-strawberry-sqlalchemy-mapper 0.8.1
Automatically generate fields for strawberry types from SQLAlchemy models.
License: MIT
Requires Python: >=3.7,<4.0
Keywords: graphql,sqlalchemy,pydantic,model

This fork is a heavily modified version of [strawberry-sqlalchemy-mapper]() with the following additions/changes:

- Implements relay pagination (using [this sqlakeyset fork](https://github.com/Apakottur/sqlakeyset))
- Fully async
- Uses SQLAlchmy 2.0 style
- Pydantic integration (generated types can also be pydantic models)

# strawberry-sqlalchemy-mapper


Strawberry-sqlalchemy-mapper is the simplest way to implement autogenerated strawberry types for columns and relationships in SQLAlchemy models.


- Instead of manually listing every column and relationship in a SQLAlchemy model, strawberry-sqlalchemy-mapper
lets you decorate a class declaration and it will automatically generate the necessary strawberry fields
for all columns and relationships (subject to the limitations below) in the given model.

- Native support for most of SQLAlchemy's most common types.
- Extensible to arbitrary custom SQLAlchemy types.
- Automatic batching of queries, avoiding N+1 queries when getting relationships
- Support for SQLAlchemy >=1.4.x
- Lightweight and fast.

## Getting Started

strawberry-sqlalchemy-mapper is available on [PyPi](https://pypi.org/project/strawberry-sqlalchemy-mapper/)

```
pip install strawberry-sqlalchemy-mapper
```


First, define your sqlalchemy model:

```python
# models.py
from sqlalchemy import Column, Integer, String
from sqlalchemy.ext.declarative import declarative_base

Base = declarative_base()

class Employee(Base):
    __tablename__ = 'employee'
    id = Column(UUID, primary_key=True)
    name = Column(String, nullable=False)
    password_hash = Column(String, nullable=False)
    department_id = Column(UUID, ForeignKey('department.id'))
    department = relationship('Department', back_populates='employees')

class Department(Base):
    __tablename__ = "department"
    id = Column(UUID, primary_key=True)
    name = Column(String, nullable=False)
    employees = relationship('Employee', back_populates='department')
```

Next, decorate a type with `strawberry_sqlalchemy_mapper.type()`
to register it as a strawberry type for the given SQLAlchemy model.
This will automatically add fields for the model's columns, relationships, association proxies,
and hybrid properties. For example:

```python
# elsewhere
# ...
from strawberry_sqlalchemy_mapper import StrawberrySQLAlchemyMapper

strawberry_sqlalchemy_mapper = StrawberrySQLAlchemyMapper()
@strawberry_sqlalchemy_mapper.type(models.Employee)
class Employee:
    __exclude__ = ["password_hash"]


@strawberry_sqlalchemy_mapper.type(models.Department)
class Department:
    pass

@strawberry.type
class Query:
    @strawberry.field
    def departments(self):
        return db.session.scalars(select(models.Department)).all()


# context is expected to have an instance of StrawberrySQLAlchemyLoader
class CustomGraphQLView(GraphQLView):
    def get_context(self):
        return {
            "sqlalchemy_loader": StrawberrySQLAlchemyLoader(bind=YOUR_SESSION),
        }

# call finalize() before using the schema:
# (note that models that are related to models that are in the schema
# are automatically mapped at this stage -- e.g., Department is mapped
# because employee.department is a relationshp to Department)
strawberry_sqlalchemy_mapper.finalize()
# only needed if you have polymorphic types
additional_types = list(strawberry_sqlalchemy_mapper.mapped_types.values())
schema = strawberry.Schema(
    query=Query,
    mutation=Mutation,
    extensions=extensions,
    types=additional_types,
)

# You can now query, e.g.:
"""
query {
    departments {
        id
        name
        employees {
            edge {
                node {
                    id
                    name
                    department {
                        # Just an example of nested relationships
                        id
                        name
                    }
                }
            }
        }
    }
}
"""
```

## Limitations

SQLAlchemy Models -> Strawberry Types and Interfaces are expected to have a consistent
(customizable) naming convention. These can be configured by passing `model_to_type_name`
and `model_to_interface_name` when constructing the mapper.

Natively supports the following SQLAlchemy types:

```python
Integer: int,
Float: float,
BigInteger: int,
Numeric: Decimal,
DateTime: datetime,
Date: date,
Time: time,
String: str,
Text: str,
Boolean: bool,
Unicode: str,
UnicodeText: str,
SmallInteger: int,
SQLAlchemyUUID: uuid.UUID,
VARCHAR: str,
ARRAY[T]: List[T] # PostgreSQL array
Enum: (the Python enum it is mapped to, which should be @strawberry.enum-decorated)
```

Additional types can be supported by passing `extra_sqlalchemy_type_to_strawberry_type_map`,
although support for `TypeDecorator` types is untested.

Association proxies are expected to be of the form `association_proxy('relationship1', 'relationship2')`,
i.e., both properties are expected to be relationships.

Roots of polymorphic hierarchies **are supported**, but are also expected to be registered via
`strawberry_sqlalchemy_mapper.interface()`, and its concrete type and
its descendants are expected to inherit from the interface:

```python
class Book(Model):
    id = Column(UUID, primary_key=True)

class Novel(Book):
    pass

class ShortStory(Book):
    pass


# in another file
strawberry_sqlalchemy_mapper = StrawberrySQLAlchemyMapper()

@strawberry_sqlalchemy_mapper.interface(models.Book)
class BookInterface:
    pass

@strawberry_sqlalchemy_mapper.type(models.Book)
class Book:
    pass

@strawberry_sqlalchemy_mapper.type(models.Novel)
class Novel:
    pass

@strawberry_sqlalchemy_mapper.type(models.ShortStory)
class ShortStory:
    pass
```

## Contributing

We encourage you to contribute to strawberry-sqlalchemy-mapper! Any contributions you make are greatly appreciated.

If you have a suggestion that would make this better, please fork the repo and create a pull request. Don't forget to give the project a star! Thanks again!

1. Fork the Project
2. Create your Feature Branch (git checkout -b feature)
3. Commit your Changes (git commit -m 'Add some feature')
4. Push to the Branch (git push origin feature)
5. Open a Pull Request


### Prerequisites

This project uses `pre-commit`_, please make sure to install it before making any
changes::

    pip install pre-commit
    cd strawberry-sqlalchemy-mapper
    pre-commit install

It is a good idea to update the hooks to the latest version::

    pre-commit autoupdate

Don't forget to tell your contributors to also install and use pre-commit.

### Installation

```bash
pip install -r requirements.txt
```

### Test

```bash
pytest
```

## ⚖️ LICENSE

MIT © [strawberry-sqlalchemy-mapper](LICENSE.txt)