gistfile1.py

class Table(Base):
    __tablename__ = 'tables'
    id = Column(Integer, primary_key=True)

    user_tables = relation("UserTable", backref='table', cascade="all, delete, delete-orphan")
    users = association_proxy("user_tables", "user")

class UserTable(Base):
    __tablename__ = "user_tables"
    
    user_id = Column(Integer, ForeignKey("users.id"), primary_key=True)
    table_id = Column(Integer, ForeignKey("tables.id"), primary_key=True)
    
    uuid = Column(String(32), unique=True, nullable=False, default=generate_uuid, index=True)

class User(Base):
    __tablename__ = "users"
    
    id = Column(Integer, primary_key=True)
    username = Column(String(32), unique=True, nullable=False)
    user_tables = relation("UserTable", backref='user', cascade="all, delete, delete-orphan")
    tables = association_proxy("user_tables", "table")