eralchemy

from sqlalchemy import create_engine, Column, Integer, String, ForeignKey from sqlalchemy.ext.declarative import declarative_base from sqlalchemy.orm import sessionmaker, relationship from eralchemy import render_er import os # 1. Define SQLAlchemy models Base = declarative_base() class User(Base): __tablename__ = 'users' id = Column(Integer, primary_key=True) name = Column(String(50), nullable=False) emails = relationship('Email', back_populates='user') class Email(Base): __tablename__ = 'emails' id = Column(Integer, primary_key=True) address = Column(String(100), nullable=False, unique=True) user_id = Column(Integer, ForeignKey('users.id')) user = relationship('User', back_populates='emails') # 2. Create a dummy database and tables db_url = "sqlite:///./er_example.db" engine = create_engine(db_url) Base.metadata.create_all(engine) # 3. Generate the ER diagram output_file = "er_diagram.png" # IMPORTANT: Graphviz must be installed on your system for this to work. # Instructions for common OS: # - Debian/Ubuntu: sudo apt-get install graphviz # - macOS: brew install graphviz # - Windows: Download and install from graphviz.org, then add to PATH. try: render_er(db_url, output_file) print(f"ER diagram generated to {output_file}") print(f"To view it, ensure Graphviz is installed and open {output_file}") except Exception as e: print(f"Failed to generate ER diagram. Ensure Graphviz is correctly installed and in your system's PATH. Error: {e}") finally: # Clean up the dummy database file if it was created if os.path.exists("./er_example.db"): pass # os.remove("./er_example.db") # Uncomment to remove DB file after run