old_contents: # stdlib
  from typing import Any
  
  # third party
  from sqlalchemy import Column
  from sqlalchemy import LargeBinary
  from sqlalchemy import String
  from sqlalchemy import Float
  
  # syft absolute
  from syft import deserialize
  from syft import serialize
  
  # relative
  from . import Base
  
  
  class Ledger(Base):
      __tablename__ = "ledger"
  
      id = Column(String(256), primary_key=True)
      entity_name = Column(String(256))
      mechanism_name = Column(String(256))
      max_budget = Column(Float())
      delta = Column(Float())
      mechanism_bin = Column(LargeBinary(3072))
      entity_bin = Column(LargeBinary(3072))
  
      @property
      def mechanism(self) -> Any:
          return deserialize(self.mechanism_bin, from_bytes=True)  # TODO: techdebt fix
  
      @mechanism.setter
      def mechanism(self, value: Any) -> None:
          self.mechanism_bin = serialize(value, to_bytes=True)  # TODO: techdebt fix
  
      @property
      def entity(self) -> Any:
          return deserialize(self.entity_bin, from_bytes=True)  # TODO: techdebt fix
  
      @entity.setter
      def entity(self, value: Any) -> None:
          self.entity_bin = serialize(value, to_bytes=True)  # TODO: techdebt fix
  
new_contents: # stdlib
  from typing import Any
  
  # third party
  from sqlalchemy import Column
  from sqlalchemy import LargeBinary
  from sqlalchemy import String
  from sqlalchemy import Integer
  from sqlalchemy import ForeignKey
  
  # syft absolute
  from syft import deserialize
  from syft import serialize
  
  # relative
  from . import Base
  
  
  class Ledger(Base):
      __tablename__ = "ledger"
  
      id = Column(Integer(), primary_key=True, autoincrement=True)
      entity_name = Column(String(256), ForeignKey("entity.name"))
      mechanism_id = Column(Integer(), ForeignKey("mechanism.id"))
  
subject: Update Ledger database table