I understand. I define my tables like
Table('tablename', metadata, Column('time', DateTime(timezone=True),
nullable=False))
Can I simply replace DateTime with SDateTime and use timezone=True, or
I'd need to add some initializer args for timezone?
Zsolt
On Fri, 25 Jan 2019 at 03:58, Mike Bayer <mike...@zzzcomputing.com> wrote:
>
> On Thu, Jan 24, 2019 at 9:07 PM Zsolt Ero <zsolt....@gmail.com> wrote:
> >
> > Do I understand it right that there is no approach which could print a
> > query without the need to modify it, if it contains datetimes?
> >
> > If so, how can I turn a where statement into something which is
> > printable using SDateTime?
> >
> > .where(trips.c.end_time >= datetime.datetime.now())
>
> where you define your Table and its column called end_time, don't use
> DateTime, use your custom version of that type.
>
> if you are relying upon reflection, use a column_reflect event
> (https://docs.sqlalchemy.org/en/latest/core/events.html?highlight=column_reflect#sqlalchemy.events.DDLEvents.column_reflect)
> to replace occurrences of DateTime with the custom DateTime object.
>
>
> SQLAlchemy can of course eventually support rendering datetimes as
> literal strings but this becomes a slippery slope where it has to
> support literal rendering for every possible type, and we're then in a
> place where we are reimplementing what the DBAPI already does and I
> don't like to be doing that. We likely could benefit from a hook
> that works like @compiles here but that's not available at this
> moment.
>
>
>
>
>
> >
> > Zsolt
> >
> > On Mon, 21 Jan 2019 at 19:22, Mike Bayer <mike...@zzzcomputing.com> wrote:
> > >
> > > On Mon, Jan 21, 2019 at 12:23 PM Zsolt Ero <zsolt....@gmail.com> wrote:
> > > >
> > > > Thanks it works perfectly, even with datetimes!
> > > >
> > > > Can I do something similar to make
> > > >
> > > > stmt.compile(dialect=postgresql.dialect(),
> > > > compile_kwargs={"literal_binds": True})
> > > >
> > > > compatible with datetime? Or maybe not this, but I'm looking for a way
> > > > to print a statement which I could copy and paste into psql console.
> > >
> > > that's what literal_binds is for but it doesn't support formatting
> > > every kind of type directly, so I assume you're getting an error
> > > message, at the moment the literal_processor can't be injected so you
> > > have to use a new type:
> > >
> > > from sqlalchemy import *
> > > from sqlalchemy.dialects import postgresql
> > > from sqlalchemy.ext.compiler import compiles
> > > import datetime
> > >
> > >
> > > class SDateTime(TypeDecorator):
> > > impl = DateTime
> > >
> > > def literal_processor(self, dialect):
> > > return lambda value: str(value)
> > >
> > >
> > > print(
> > > select([column("q", SDateTime) == datetime.datetime.now()]).compile(
> > > dialect=postgresql.dialect(),
> > > compile_kwargs=dict(literal_binds=True)
> > > )
> > > )
> > >
> > >
> > >
> > >
> > > >
> > > > Zsolt
> > > >
> > > > --
> > > > SQLAlchemy -
> > > > The Python SQL Toolkit and Object Relational Mapper
> > > >
> > > > http://www.sqlalchemy.org/
> > > >
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> > >
> > > http://www.sqlalchemy.org/
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> > --
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> > The Python SQL Toolkit and Object Relational Mapper
> >
> > http://www.sqlalchemy.org/
> >
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> --
> 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.
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--
SQLAlchemy -
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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.
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