Question

Is it possible to create Column in SQLAlchemy which is going to be automatically populated with time when it inserted/updated last time ?

I created models, inherited from Base class

class Base(object):
    def __tablename__(self):
        return self.__name__.lower()
    id = Column(Integer, primary_key=True)
    last_time = Column(TIMESTAMP, server_default=func.now())

Base = declarative_base(cls=Base)

class EntityModel(Base):
    __tablename__ = 'entities'
    settlement_id = Column(Integer, ForeignKey('settlements.id'), nullable=False)
    type = Column(String(20), nullable=False)
    level = Column(Integer, nullable=False, default=0)
    energy = Column(Float, nullable=False, default=0)
    position_x = Column(Integer, default=0)
    position_y = Column(Integer, default=0)

    def __repr__(self):
        return "<Entity('%s')>" % (self.type)

Every time when I update EntityModel I want to the last_time be updated on system function.now(). I can do this on the database level with triggers but I would rather do on application level if is it possible.

Answer 1

In Base class add onupdate in the last statement as follows:

from sqlalchemy.sql import func

last_time = Column(TIMESTAMP, server_default=func.now(), onupdate=func.current_timestamp())