# 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: BigInt,
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
JSON: JSON # SQLAlchemy JSON
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
```
Install [PostgreSQL 14+](https://www.postgresql.org/download/)
### Test
```bash
pytest
```
## ⚖️ LICENSE
MIT © [strawberry-sqlalchemy-mapper](LICENSE.txt)
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"description": "# strawberry-sqlalchemy-mapper\n\n\nStrawberry-sqlalchemy-mapper is the simplest way to implement autogenerated strawberry types for columns and relationships in SQLAlchemy models.\n\n\n- Instead of manually listing every column and relationship in a SQLAlchemy model, strawberry-sqlalchemy-mapper\nlets you decorate a class declaration and it will automatically generate the necessary strawberry fields\nfor all columns and relationships (subject to the limitations below) in the given model.\n\n- Native support for most of SQLAlchemy's most common types.\n- Extensible to arbitrary custom SQLAlchemy types.\n- Automatic batching of queries, avoiding N+1 queries when getting relationships\n- Support for SQLAlchemy >=1.4.x\n- Lightweight and fast.\n\n## Getting Started\n\nstrawberry-sqlalchemy-mapper is available on [PyPi](https://pypi.org/project/strawberry-sqlalchemy-mapper/)\n\n```\npip install strawberry-sqlalchemy-mapper\n```\n\n\nFirst, define your sqlalchemy model:\n\n```python\n# models.py\nfrom sqlalchemy import Column, Integer, String\nfrom sqlalchemy.ext.declarative import declarative_base\n\nBase = declarative_base()\n\n\nclass Employee(Base):\n __tablename__ = \"employee\"\n id = Column(UUID, primary_key=True)\n name = Column(String, nullable=False)\n password_hash = Column(String, nullable=False)\n department_id = Column(UUID, ForeignKey(\"department.id\"))\n department = relationship(\"Department\", back_populates=\"employees\")\n\n\nclass Department(Base):\n __tablename__ = \"department\"\n id = Column(UUID, primary_key=True)\n name = Column(String, nullable=False)\n employees = relationship(\"Employee\", back_populates=\"department\")\n```\n\nNext, decorate a type with `strawberry_sqlalchemy_mapper.type()`\nto register it as a strawberry type for the given SQLAlchemy model.\nThis will automatically add fields for the model's columns, relationships, association proxies,\nand hybrid properties. For example:\n\n```python\n# elsewhere\n# ...\nfrom strawberry_sqlalchemy_mapper import StrawberrySQLAlchemyMapper\n\nstrawberry_sqlalchemy_mapper = StrawberrySQLAlchemyMapper()\n\n\n@strawberry_sqlalchemy_mapper.type(models.Employee)\nclass Employee:\n __exclude__ = [\"password_hash\"]\n\n\n@strawberry_sqlalchemy_mapper.type(models.Department)\nclass Department:\n pass\n\n\n@strawberry.type\nclass Query:\n @strawberry.field\n def departments(self):\n return db.session.scalars(select(models.Department)).all()\n\n\n# context is expected to have an instance of StrawberrySQLAlchemyLoader\nclass CustomGraphQLView(GraphQLView):\n def get_context(self):\n return {\n \"sqlalchemy_loader\": StrawberrySQLAlchemyLoader(bind=YOUR_SESSION),\n }\n\n\n# call finalize() before using the schema:\n# (note that models that are related to models that are in the schema\n# are automatically mapped at this stage -- e.g., Department is mapped\n# because employee.department is a relationshp to Department)\nstrawberry_sqlalchemy_mapper.finalize()\n# only needed if you have polymorphic types\nadditional_types = list(strawberry_sqlalchemy_mapper.mapped_types.values())\nschema = strawberry.Schema(\n query=Query,\n mutation=Mutation,\n extensions=extensions,\n types=additional_types,\n)\n\n# You can now query, e.g.:\n\"\"\"\nquery {\n departments {\n id\n name\n employees {\n edge {\n node {\n id\n name\n department {\n # Just an example of nested relationships\n id\n name\n }\n }\n }\n }\n }\n}\n\"\"\"\n```\n\n## Limitations\n\nSQLAlchemy Models -> Strawberry Types and Interfaces are expected to have a consistent\n(customizable) naming convention. These can be configured by passing `model_to_type_name`\nand `model_to_interface_name` when constructing the mapper.\n\nNatively supports the following SQLAlchemy types:\n\n```python\nInteger: int,\nFloat: float,\nBigInteger: BigInt,\nNumeric: Decimal,\nDateTime: datetime,\nDate: date,\nTime: time,\nString: str,\nText: str,\nBoolean: bool,\nUnicode: str,\nUnicodeText: str,\nSmallInteger: int,\nSQLAlchemyUUID: uuid.UUID,\nVARCHAR: str,\nARRAY[T]: List[T] # PostgreSQL array\nJSON: JSON # SQLAlchemy JSON\nEnum: (the Python enum it is mapped to, which should be @strawberry.enum-decorated)\n```\n\nAdditional types can be supported by passing `extra_sqlalchemy_type_to_strawberry_type_map`,\nalthough support for `TypeDecorator` types is untested.\n\nAssociation proxies are expected to be of the form `association_proxy('relationship1', 'relationship2')`,\ni.e., both properties are expected to be relationships.\n\nRoots of polymorphic hierarchies **are supported**, but are also expected to be registered via\n`strawberry_sqlalchemy_mapper.interface()`, and its concrete type and\nits descendants are expected to inherit from the interface:\n\n```python\nclass Book(Model):\n id = Column(UUID, primary_key=True)\n\n\nclass Novel(Book):\n pass\n\n\nclass ShortStory(Book):\n pass\n\n\n# in another file\nstrawberry_sqlalchemy_mapper = StrawberrySQLAlchemyMapper()\n\n\n@strawberry_sqlalchemy_mapper.interface(models.Book)\nclass BookInterface:\n pass\n\n\n@strawberry_sqlalchemy_mapper.type(models.Book)\nclass Book:\n pass\n\n\n@strawberry_sqlalchemy_mapper.type(models.Novel)\nclass Novel:\n pass\n\n\n@strawberry_sqlalchemy_mapper.type(models.ShortStory)\nclass ShortStory:\n pass\n```\n\n## Contributing\n\nWe encourage you to contribute to strawberry-sqlalchemy-mapper! Any contributions you make are greatly appreciated.\n\nIf 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!\n\n1. Fork the Project\n2. Create your Feature Branch (git checkout -b feature)\n3. Commit your Changes (git commit -m 'Add some feature')\n4. Push to the Branch (git push origin feature)\n5. Open a Pull Request\n\n\n### Prerequisites\n\nThis project uses `pre-commit`_, please make sure to install it before making any\nchanges::\n\n pip install pre-commit\n cd strawberry-sqlalchemy-mapper\n pre-commit install\n\nIt is a good idea to update the hooks to the latest version::\n\n pre-commit autoupdate\n\nDon't forget to tell your contributors to also install and use pre-commit.\n\n### Installation\n\n```bash\npip install -r requirements.txt\n```\n\nInstall [PostgreSQL 14+](https://www.postgresql.org/download/)\n\n### Test\n\n```bash\npytest\n```\n\n## \u2696\ufe0f LICENSE\n\nMIT \u00a9 [strawberry-sqlalchemy-mapper](LICENSE.txt)\n",
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