Hello Simon,
One extra question:
Do you know maybe how to assign NULL field value to numeric type field
using sqlalchemy? I change field to some numeric value and then I want to
clear this field.
I tried assign None as default for value parameter:
[image: apt2.jpg]
But I receive:
"Implicit conversion from datatype 'VARCHAR' to 'NUMERIC' is not allowed.
Use the CONVERT function to run this query."
W dniu piątek, 12 lipca 2019 11:53:58 UTC+2 użytkownik Simon King napisał:
>
> If SQLAlchemy didn't support the second calling style, you would still
> be able to make this work using the Python "**" operator:
>
> updatevalues = {custom_column: value}
> query = AIRPORT.update().values(**updatevalues)
>
> When calling a function, passing "**somedictionary" is equivalent to
> passing each of the dictionary elements as keyword arguments to the
> function.
>
> >>> def f(a, b, c):
> ... print("a =", a)
> ... print("b =", b)
> ... print("c =", c)
> ...
> >>> f(a=1, b=2, c=3)
> a = 1
> b = 2
> c = 3
> >>> args = {'a': 1, 'b': 2, 'c': 3}
> >>> f(**args)
> a = 1
> b = 2
> c = 3
>
> Simon
>
> On Fri, Jul 12, 2019 at 10:28 AM Mirek Morek <teste...@gmail.com
> <javascript:>> wrote:
> >
> > It works!
> >
> > Thank you very much Simon, I really appreciate that. You saved me a lot
> of nerves. I would buy you a beer if I could.
> >
> > So, in general we can say that only second calling style works in my
> example.
> >
> > Regards.
> >
> > W dniu czwartek, 11 lipca 2019 16:35:25 UTC+2 użytkownik Simon King
> napisał:
> >>
> >> Here are the docs for the Update.values() method:
> >>
> >>
> https://docs.sqlalchemy.org/en/13/core/dml.html#sqlalchemy.sql.expression.Update.values
>
> >>
> >> Note that it supports two main calling styles, either keyword
> arguments:
> >>
> >> .values(name_column='cat')
> >>
> >> ...or passing a dictionary:
> >>
> >> .values({'name_column': 'cat'})
> >>
> >> Since you want to choose the column dynamically, you can use the
> >> dictionary style:
> >>
> >> updatevalues = {custom_column: value}
> >> query = AIRPORT.update().values(updatevalues)
> >>
> >> Hope that helps,
> >>
> >> Simon
> >>
> >> On Thu, Jul 11, 2019 at 3:00 PM Mirek Morek <teste...@gmail.com>
> wrote:
> >> >
> >> > Hello everyone,
> >> > I have a following question:
> >> >
> >> > I use sqlalchemy within my python method as follows:
> >> >
> >> >
> >> > I want to be able to replace 'custom_column' with parameter passed in
> the method. The same way as it works fine for airport_sys_id,
> project_sys_id and value.
> >> >
> >> > For example I want to pass in my method (1, 2, name_column, cat) and
> receive as follows:
> >> >
> >> > query = AIRPORT.update(). \
> >> > where(AIRPORT.c.airport_sys_id == 1). \
> >> > where(AIRPORT.c.project_sys_id == 2). \
> >> > values(name_column=cat)
> >> >
> >> > I searched all I could but with no success. I would be extremely
> thankful for your support. Regards.
> >> >
> >> >
> >> > --
> >> > 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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>
>
> >> > For more options, visit https://groups.google.com/d/optout.
> >
> > --
> > 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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>
>
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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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