Loading Specific User Fields with SQLAlchemy-Utils

This function uses the load_only option from SQLAlchemy-Utils library to load only specific fields of a record from the database.

Technology Stack : SQLAlchemy-Utils, SQLAlchemy

Code Type : Function

Code Difficulty : Intermediate

                
                    
from sqlalchemy.orm import load_only
from sqlalchemy import create_engine, Column, Integer, String
from sqlalchemy.ext.declarative import declarative_base

# Define a base class for declarative class definitions
Base = declarative_base()

# Define a simple model
class User(Base):
    __tablename__ = 'users'
    id = Column(Integer, primary_key=True)
    name = Column(String)

# Function to load only certain fields of a model
def load_user_fields(user_id, fields):
    engine = create_engine('sqlite:///:memory:')
    Base.metadata.create_all(engine)
    session = engine.connect()
    
    # Load the user with only the specified fields
    user = session.query(User).options(load_only(*fields)).get(user_id)
    
    session.close()
    return user

# JSON representation of the function