Re: [sqlalchemy] How to implement SQL level expression for this hybrid property?

On Mon, Oct 3, 2016 at 11:43 AM, Jinghui Niu wrote: > This really helps. Thank you Simon! I still have a couple of smaller > questions. > >> When you access .fullname, the "self" parameter is now the >> *class*, so self.firstname and self.lastname are SQLAlchemy column >>

Re: [sqlalchemy] How to implement SQL level expression for this hybrid property?

This really helps. Thank you Simon! I still have a couple of smaller questions. When you access .fullname, the "self" parameter is now the > *class*, so self.firstname and self.lastname are SQLAlchemy column > properties. Here by *column properties* do you mean the object returned by

Re: [sqlalchemy] How to implement SQL level expression for this hybrid property?

The first example from the docs is illustrating the most simple case, where the function happens to work at both the instance and class level. Here's the example: class User(Base): __tablename__ = 'user' id = Column(Integer, primary_key=True) firstname = Column(String(50))

Re: [sqlalchemy] How to implement SQL level expression for this hybrid property?

> > User.firstname is not the value from any particular row - it's the > (ORM-level) column object. It's a little abstruse here that a ORM-level instrumented column object, such as User.firstname works, but a true Column object, such as User.__table__.c.firstname doesn't. Maybe I misunderstood

Re: [sqlalchemy] How to implement SQL level expression for this hybrid property?

Thank you Simon. Your explanation helps me understand this quite a lot. Sometimes the documentation is so terse that only when you fully understand the subject then you can understand it by reading it:) But still if I want to implement this hybrid property from the query level, how would you

Re: [sqlalchemy] How to implement SQL level expression for this hybrid property?

On Mon, Oct 3, 2016 at 7:17 AM, Jinghui Niu wrote: > I have a ledger table and a corresponding python class. I defined the model > using SQLAlchemy, as follows, > > class Ledger(Base): > __tablename__ = 'ledger' > > currency_exchange_rate_lookup = {('CNY', 'CAD'):

[sqlalchemy] How to implement SQL level expression for this hybrid property?

I have a ledger table and a corresponding python class. I defined the model using SQLAlchemy, as follows, class Ledger(Base): __tablename__ = 'ledger' currency_exchange_rate_lookup = {('CNY', 'CAD'): 0.2} amount = Column(Numeric(10, 2), nullable=False) currency =