I'm sorry, I still don't understand - what do you expect query(Genome.attributes) to do? Can you give an example?
Thanks, Simon On Wed, Jan 26, 2022 at 11:30 PM Simon <htlbyd...@gmail.com> wrote: > > Sorry for that the question is not clear. The question is how can we query a > database's property. > > Given the above example, if query(Genome.id) or query(Genome.created_date), > it works fine. But if I query the property, query(Genome.attributes): it > raises the exception. > > Thanks. > Simon > > On Wednesday, January 26, 2022 at 12:53:52 AM UTC+13 Simon King wrote: >> >> Can you show the part of *your* code that is triggering the error, and >> explain what you are trying to do? Plain python properties aren't >> normally very useful when accessed via a class. "Genome.attributes" >> returns a property object, not the return value from the function, and >> I don't understand what you are trying to do with it. >> >> Thanks, >> >> Simon >> >> On Mon, Jan 24, 2022 at 2:03 AM Simon <htlb...@gmail.com> wrote: >> > >> > Hi there, >> > >> > I got a problem about 'sqlalchemy.exc.ArgumentError: SQL expression object >> > expected, got object of type <class 'property'> instead' >> > >> > My SQLAlchemy version is 1.3.22. I have a database like >> > >> > Class Genome: >> > id = Column(Integer, primary_key=True) >> > created_date = Column(Datetime, nullable=False) >> > >> > @property >> > def attributes(self): >> > return "something" >> > >> > >> > If using the query, it reports an error through the elements.py in the >> > sqlAlchemy >> > >> > def _literal_as(element, text_fallback): >> > if isinstance(element, Visitable): >> > return element >> > elif hasattr(element, "__clause_element__"): >> > return element.__clause_element__() >> > elif isinstance(element, util.string_types): >> > return text_fallback(element) >> > elif isinstance(element, (util.NoneType, bool)): >> > return _const_expr(element) >> > else: >> > raise exc.ArgumentError( >> > "SQL expression object expected, got object of type %r " >> > "instead" % type(element) >> > ) >> > >> > This exception is not raised if I directly query genome's column name such >> > as created_date or id. >> > >> > I am wondering 1) could the column name and property be used >> > interchangeably in some way? Or say how could to query a table's property >> > in the way of querying a table's column? 2) what are some significant >> > differences between table's column name and property? >> > >> > Thanks. >> > >> > >> > >> > >> > -- >> > SQLAlchemy - >> > The Python SQL Toolkit and Object Relational Mapper >> > >> > http://www.sqlalchemy.org/ >> > >> > To post example code, please provide an MCVE: Minimal, Complete, and >> > Verifiable Example. See http://stackoverflow.com/help/mcve for a full >> > description. >> > --- >> > You received this message because you are subscribed to the Google Groups >> > "sqlalchemy" group. >> > To unsubscribe from this group and stop receiving emails from it, send an >> > email to sqlalchemy+...@googlegroups.com. >> > To view this discussion on the web visit >> > https://groups.google.com/d/msgid/sqlalchemy/7f03c9bb-9324-4e3e-8aea-cd0d46f9021bn%40googlegroups.com. > > -- > SQLAlchemy - > The Python SQL Toolkit and Object Relational Mapper > > http://www.sqlalchemy.org/ > > To post example code, please provide an MCVE: Minimal, Complete, and > Verifiable Example. See http://stackoverflow.com/help/mcve for a full > description. > --- > You received this message because you are subscribed to the Google Groups > "sqlalchemy" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to sqlalchemy+unsubscr...@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/sqlalchemy/2fbf2d83-6865-4b9b-8db6-cb5f60e0eaffn%40googlegroups.com. -- SQLAlchemy - The Python SQL Toolkit and Object Relational Mapper http://www.sqlalchemy.org/ To post example code, please provide an MCVE: Minimal, Complete, and Verifiable Example. See http://stackoverflow.com/help/mcve for a full description. --- You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To unsubscribe from this group and stop receiving emails from it, send an email to sqlalchemy+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/sqlalchemy/CAFHwexeT_AcTbbJ561Rx%3D3jDdAFxshTMHrJ7jFSzKiGMZC6Y9Q%40mail.gmail.com.
