Graphene-SQLAlchemy is a Python ORM (Object-Relational Mapping) library that simplifies working with databases using the GraphQL API. To use Graphene-SQLAlchemy to define fields in your models, you’ll need to create a model class that extends the SQLAlchemy ORM and overrides the `__table__` attribute.
(how to define fields in graphene-sqlalchemy)
Here’s an example of how to define a simple model class that uses graphene-sqlalchemy:
“`python
from graphene_sqlalchemy import SQLAlchemyModel
from sqlalchemy.ext.declarative import declarative_base
Base = declarative_base()
class MyModel(db.Model):
__tablename__ = ‘my_table’
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(20), nullable=False)
class Query(Base):
def my_query(self, params=None):
raise NotImplementedError
class Mutation(Base):
async def myMutation(self, params=None):
raise NotImplementedError
“`
In this example, we’re defining a `MyModel` class that extends the SQLAlchemyModel class provided by graphene-sqlalchemy. The `__tablename__` attribute specifies that this model should be mapped to the `my_table` table in the database.
We’re also defining two base classes: `Query` and `Mutation`. These classes will contain methods for executing GraphQL queries and mutations, respectively.
The `my_query` method will be called when a query is executed using the `query()` method on the `MyModel` class. It takes optional parameters that allow you to specify the parameters to pass to the query.
The `myMutation` method will be called when a mutation is executed using the `mutation()` method on the `MyModel` class. It takes optional parameters that allow you to specify the parameters to pass to the mutation.
By defining fields in the model class, you can easily access and manipulate data stored in the database using the GraphQL API. For example, you could define a field for the `name` property like this:
“`makefile
class MyModel(db.Model):
__tablename__ = ‘my_table’
id = db.Column(db.Integer, primary_key=True)
name = db.Column(db.String(20), nullable=False)
age = db.Column(db.Integer, nullable=False)
def __repr__(self):
return f”MyModel(id={self.id}, name={self.name}, age={self.age})”
“`
(how to define fields in graphene-sqlalchemy)
With this definition, you can access the `name` and `age` properties directly from the `MyModel` object using dot notation. You could also perform various operations on these properties, such as updating or deleting them.
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