Passing None is the right way to set a column to NULL, so it sounds like
you are doing something else wrong. How are you calling your
update_airport_reference_temperature function?
Also, enabling debug level logging (by passing echo='debug' when you create
your SQLAlchemy engine) will show exactly what values you are passing to
the database.
Simon
On Mon, Jul 15, 2019 at 10:45 AM Mirek Morek <testere...@gmail.com> wrote:
> 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> 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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>>
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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
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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
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--
SQLAlchemy -
The Python SQL Toolkit and Object Relational Mapper
http://www.sqlalchemy.org/
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