[tryton] Domain with function field

[Maxime Richez]

Hi,

In domain definition, operand cannot be a field. So, i'm wondering how doing this kind of view: for example, a listing of all products having a cost_price greater than list price.
I would define this domain ['cost_price', '>', Eval('list_price')] but this is not working.
Another idea, was to define a function field on a boolean field (flag) and the setter of this function field will return true or false about the comparison between 'cost_price' and 'list_price'... and then creating a treeview with domain ['flag', '=' ,'True'] but once again, how to define a correct domain in the searcher function of the flag function field ?
Thanks for ideas, help...

[Cédric Krier]

Post by Maxime Richez
In domain definition, operand cannot be a field. So, i'm wondering how
doing this kind of view: for example, a listing of all products having
a cost_price greater than list price.
I would define this domain ['cost_price', '>', Eval('list_price')] but this is not working.
Another idea, was to define a function field on a boolean field (flag)
and the setter of this function field will return true or false about
the comparison between 'cost_price' and 'list_price'... and then
creating a treeview with domain ['flag', '=' ,'True'] but once again,
how to define a correct domain in the searcher function of the flag
function field ?

For now, I think the Function field is the only option. The searcher
should probably have to return a clause like [('id', 'in', query)].
This is not optimal but it should work.

This is issue came up from time to time. I think it could be addresses
by extending the domain syntax. We will need to have a way to put a
column (with the option of being nested) as value. For example we could
have an object Field:

[('cost_price', '>', Field('list_price'))]

I think on the client we could have this syntax:

"Cost Price": > @"List Price"

[Maxime Richez]

Post by Cédric Krier
For now, I think the Function field is the only option. The searcher
should probably have to return a clause like [('id', 'in', query)].
This is not optimal but it should work.

2 questions:

- In the case of the function field is only used in a treeview for filtering data (just for display), isn't better to define a new modelview based on a query (for example: https://bitbucket.org/zikzakmedia/trytond-product_quantity_by_location/src ) Would it be more optimal ?

- What about the search function if one of the field to compare with another field is already a function field (for example product quantity field)? Is the only way of doing the search is still the query (that would be very complex in the case of quantity field,no ?) ?

Post by Cédric Krier
This is issue came up from time to time. I think it could be addresses
by extending the domain syntax. We will need to have a way to put a
column (with the option of being nested) as value. For example we could
[('cost_price', '>', Field('list_price'))]

Would be nice :-)

[Cédric Krier]

Post by Maxime Richez

Post by Cédric Krier
For now, I think the Function field is the only option. The searcher
should probably have to return a clause like [('id', 'in', query)].
This is not optimal but it should work.

- In the case of the function field is only used in a treeview for
filtering data (just for display), isn't better to define a new
https://bitbucket.org/zikzakmedia/trytond-product_quantity_by_location/src
) Would it be more optimal ?

A new model means new views, new access rights etc. Also module that
extend the base may need to be aware of this new model.

Post by Maxime Richez
- What about the search function if one of the field to compare with
another field is already a function field (for example product
quantity field)? Is the only way of doing the search is still the
query (that would be very complex in the case of quantity field,no ?)
?

Of course you can construct the domain by evaluating the records in
Python. But it will work only if you evaluate a small list of records.
Larger one will require to write a complex SQL query.