Graphene SQLAlchemy is a Python ORM (Object-Relational Mapping) library that provides a flexible and scalable way to interact with databases. It can be used to define and manage new fields in your database schema.
(how to define new fields graphene-sqlalchemy)
To define a new field using Graphene SQLAlchemy, you will need to create a new model class that inherits from the existing model class. You will then use the `add_column` method to add the new field to the model’s column list.
Here is an example:
“`python
from graphene_sqlalchemy import SQLAlchemyConnection
class User(db.Model):
id = db.Column(db.Integer, primary_key=True)
username = db.Column(db.String(80), unique=True, nullable=False)
email = db.Column(db.String(120), unique=True, nullable=False)
def __repr__(self):
return f”
class MyModel(db.Model):
id = db.Column(db.Integer, primary_key=True)
user_id = db.Column(db.Integer, db.ForeignKey(‘user.id’), nullable=False)
def __repr__(self):
return f”
“`
In this example, we have defined two models: `User` and `MyModel`. The `User` model has three columns: `id`, `username`, and `email`. The `MyModel` model also has a foreign key column that references the `id` column in the `User` model.
To define a new field in this schema, you can simply call the `add_column` method on the model class. For example, to add a new `name` field to the `User` model, you would do:
“`python
from graphene_sqlalchemy import SQLAlchemyConnection
class User(db.Model):
id = db.Column(db.Integer, primary_key=True)
username = db.Column(db.String(80), unique=True, nullable=False)
email = db.Column(db.String(120), unique=True, nullable=False)
name = db.Column(db.String(200), nullable=False)
def __repr__(self):
return f”
class MyModel(db.Model):
id = db.Column(db.Integer, primary_key=True)
user_id = db.Column(db.Integer, db.ForeignKey(‘user.id’), nullable=False)
def __repr__(self):
return f”
“`
In this example, we have added a new `name` field to the `User` model by calling the `add_column` method and passing it the string value for the new field as the argument. This will add the new field to the model’s column list and make it available for querying the database.
(how to define new fields graphene-sqlalchemy)
Note that the `add_column` method takes one or more arguments, including the name of the field, its data type, and any options that may be passed through to the ORM class. If you are using multiple columns in the same model, you should specify their order using the `order_by` option.
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