Discover how a bimodal integration strategy can address the major data management challenges facing your organization today.
Get the Report →How to use SQLAlchemy ORM to access GraphQL Data in Python
Create Python applications and scripts that use SQLAlchemy Object-Relational Mappings of GraphQL data.
The rich ecosystem of Python modules lets you get to work quickly and integrate your systems effectively. With the CData Python Connector for GraphQL and the SQLAlchemy toolkit, you can build GraphQL-connected Python applications and scripts. This article shows how to use SQLAlchemy to connect to GraphQL data to query GraphQL data.
With built-in optimized data processing, the CData Python Connector offers unmatched performance for interacting with live GraphQL data in Python. When you issue complex SQL queries from GraphQL, the CData Connector pushes supported SQL operations, like filters and aggregations, directly to GraphQL and utilizes the embedded SQL engine to process unsupported operations client-side (often SQL functions and JOIN operations).
Connecting to GraphQL Data
Connecting to GraphQL data looks just like connecting to any relational data source. Create a connection string using the required connection properties. For this article, you will pass the connection string as a parameter to the create_engine function.
You must specify the URL of the GraphQL service. The driver supports two types of authentication:
- Basic: Set AuthScheme to Basic. You must specify the User and Password of the GraphQL service.
- OAuth 1.0 & 2.0: Take a look at the OAuth section in the Help documentation for detailed instructions.
Follow the procedure below to install SQLAlchemy and start accessing GraphQL through Python objects.
Install Required Modules
Use the pip utility to install the SQLAlchemy toolkit and SQLAlchemy ORM package:
pip install sqlalchemy
pip install sqlalchemy.orm
Be sure to import the appropriate modules:
from sqlalchemy import create_engine, String, Column
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker
Model GraphQL Data in Python
You can now connect with a connection string. Use the create_engine function to create an Engine for working with GraphQL data.
NOTE: Users should URL encode the any connection string properties that include special characters. For more information, refer to the SQL Alchemy documentation.
engine = create_engine("graphql:///?AuthScheme=Basic&User=username&Password=password&URL=https://mysite.com&InitiateOAuth=GETANDREFRESH&OAuthSettingsLocation=/PATH/TO/OAuthSettings.txt")
Declare a Mapping Class for GraphQL Data
After establishing the connection, declare a mapping class for the table you wish to model in the ORM (in this article, we will model the Users table). Use the sqlalchemy.ext.declarative.declarative_base function and create a new class with some or all of the fields (columns) defined.
base = declarative_base()
class Users(base):
__tablename__ = "Users"
Name = Column(String,primary_key=True)
Email = Column(String)
...
Query GraphQL Data
With the mapping class prepared, you can use a session object to query the data source. After binding the Engine to the session, provide the mapping class to the session query method.
Using the query Method
engine = create_engine("graphql:///?AuthScheme=Basic&User=username&Password=password&URL=https://mysite.com&InitiateOAuth=GETANDREFRESH&OAuthSettingsLocation=/PATH/TO/OAuthSettings.txt")
factory = sessionmaker(bind=engine)
session = factory()
for instance in session.query(Users).filter_by(UserLogin="admin"):
print("Name: ", instance.Name)
print("Email: ", instance.Email)
print("---------")
Alternatively, you can use the execute method with the appropriate table object. The code below works with an active session.
Using the execute Method
Users_table = Users.metadata.tables["Users"]
for instance in session.execute(Users_table.select().where(Users_table.c.UserLogin == "admin")):
print("Name: ", instance.Name)
print("Email: ", instance.Email)
print("---------")
For examples of more complex querying, including JOINs, aggregations, limits, and more, refer to the Help documentation for the extension.
Free Trial & More Information
Download a free, 30-day trial of the CData Python Connector for GraphQL to start building Python apps and scripts with connectivity to GraphQL data. Reach out to our Support Team if you have any questions.