El martes, 17 de abril de 2018, 9:11:23 (UTC-3), Josh Smeaton escribió:
>
> Have you looked into using Cast for this particular query to see if it
> passes?
>
> https://docs.djangoproject.com/en/2.0/ref/models/database-functions/#cast
>
> Cast(RawSQL('%s', ['value']), CharField(max_length=10) ?
>
> If that worked, then perhaps you could find a clever way to wrap problem
> expressions, or at least document the workaround for your users.
>
Ok, it worked rigth. It is a good started point and solve the problem.
I will need to dig a little more to found out a better solution.
Thanks.
>
> On Tuesday, 17 April 2018 21:12:09 UTC+10, Maximiliano Robaina wrote:
>>
>>
>> Hi Shai,
>>
>> Thank for the tip
>>
>> El martes, 17 de abril de 2018, 3:01:30 (UTC-3), Shai Berger escribió:
>>>
>>> Hi Maximiliano,
>>>
>>> On Sat, 14 Apr 2018 19:25:48 -0700 (PDT)
>>> Maximiliano Robaina <maxir...@gmail.com> wrote:
>>>
>>> > Hi,
>>> >
>>> > Testing expressions test app, the query generated into
>>> > BasicExpressionsTests.test_annotate_values_filter method:
>>> >
>>> > companies = Company.objects.annotate(
>>> > foo=RawSQL('%s', ['value']),
>>> > ).filter(foo='value').order_by('name')
>>> >
>>> > Generate:
>>> >
>>> > 'SELECT "EXPRESSIONS_COMPANY"."ID", "EXPRESSIONS_COMPANY"."NAME",
>>> > "EXPRESSIONS_COMPANY"."NUM_EMPLOYEES",
>>> > "EXPRESSIONS_COMPANY"."NUM_CHAIRS", "EXPRESSIONS_COMPANY"."CEO_ID",
>>> > "EXPRESSIONS_COMPANY"."POINT_OF_CONTACT_ID", ? AS "FOO" FROM
>>> > "EXPRESSIONS_COMPANY" WHERE ? = ? ORDER BY
>>> > "EXPRESSIONS_COMPANY"."NAME" ASC'
>>> >
>>> > This sql command has 3 params (?), two of which are out of where
>>> > clause.
>>> >
>>> > ? AS "FOO"
>>> >
>>> > WHERE ? = ?
>>> >
>>>
>>> A few years ago something similar was causing issues with the Oracle
>>> backend. To resolve it, Mariusz added a clevar hack, relying on named
>>> parameters -- he made sure that if the same parameter value is used
>>> more than once, then the statement re-uses the parameter name, passing
>>> the value only once. So, in your case, the equivalent would be
>>> something like
>>>
>>> ...
>>> "EXPRESSIONS_COMPANY"."POINT_OF_CONTACT_ID", %arg1 AS "FOO" FROM
>>> "EXPRESSIONS_COMPANY" WHERE %arg1 = %arg1 ORDER BY
>>> "EXPRESSIONS_COMPANY"."NAME" ASC'
>>>
>>> with
>>>
>>> cursor.execute(sql, [], arg1='value')
>>>
>>> This was relatively easy to do in the Oracle backend, which has always
>>> used named parameters under the hood (though the idea to do it was, in
>>> my opinion, surprising and brilliant). If Firebird supports them, you
>>> may be able to borrow this solution.
>>>
>>> Shai
>>>
>>
>> Ok, but it is a cx_Oracle implementation.
>> Unfortunately fdb (the firebird python driver) doesn't support this and,
>> in any case, is a FirebirdSQL limitation. [1]
>>
>> Regards.
>>
>>
>> [1]
>> https://stackoverflow.com/questions/37348807/data-type-unknown-in-case-expression-with-only-parameters-as-values
>>
>>
>>
>
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