virtual fields
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mr.freeze
Oct 31, 2009, 2:16:42 PM10/31/09
to web2py-users
Virtual fields are my new favorite thing. Currently you must call
setvirtualfields after each select. What about adding the ability to
setvirtualfields at the Table level so that any select will call
setvirtualfields automatically? Pseudocode:
db.define_table('mytable',Field('cost'),Field('quantity'))
class ComputedFields:
def amount(self):
return self.mytable.cost*self.mytable.quantity
db.mytable.setvirtualfields(total=ComputedFields())
What do you think?
setvirtualfields after each select. What about adding the ability to
setvirtualfields at the Table level so that any select will call
setvirtualfields automatically? Pseudocode:
db.define_table('mytable',Field('cost'),Field('quantity'))
class ComputedFields:
def amount(self):
return self.mytable.cost*self.mytable.quantity
db.mytable.setvirtualfields(total=ComputedFields())
What do you think?
Douglas Soares de Andrade
Oct 31, 2009, 3:00:57 PM10/31/09
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Em Sat, 31 Oct 2009 11:16:42 -0700 (PDT)
"mr.freeze" <nat...@freezable.com> escreveu:
"mr.freeze" <nat...@freezable.com> escreveu:
Hi,
+1 for me, i liked this syntax and it seems very easy to understand.
mdipierro
Oct 31, 2009, 4:04:32 PM10/31/09
to web2py-users
I like it but with some caveats. In
rows.setvirtualfields(total=ComputedFields())
we need to specify total to clarify the table or virtualtable the
virtualfields are attached to.
when attaching virtualfields to a table there is no need to specify
that.
So I think it should just be:
table.addvirtualfields(ComputeFields())
Implementation:
The argument would be appended to
table._virtualfields=[]
and the latter would be precessed by
Set.parse
that for each element table._virtualfields would call
setvirtualfields
rows.setvirtualfields(total=ComputedFields())
we need to specify total to clarify the table or virtualtable the
virtualfields are attached to.
when attaching virtualfields to a table there is no need to specify
that.
So I think it should just be:
table.addvirtualfields(ComputeFields())
Implementation:
The argument would be appended to
table._virtualfields=[]
and the latter would be precessed by
Set.parse
that for each element table._virtualfields would call
setvirtualfields
mdipierro
Oct 31, 2009, 4:31:46 PM10/31/09
to web2py-users
or just
db.table.virtualfields.add(ComputedFields())
as a lazy
rows.setvirtualfields(table=ComputedFields())
it can be implemented in two lines if ok.
Massimo
db.table.virtualfields.add(ComputedFields())
as a lazy
rows.setvirtualfields(table=ComputedFields())
it can be implemented in two lines if ok.
Massimo
mr.freeze
Oct 31, 2009, 4:45:10 PM10/31/09
to web2py-users
virtualfields.append not add, right? Sounds good to me. Shall I take
a crack at it or do you already have it in trunk :)
a crack at it or do you already have it in trunk :)
Joe Barnhart
Oct 31, 2009, 4:45:24 PM10/31/09
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I admit I'm not "up" on virtual fields. I didn't notice them when they were added. I'm wondering if they carry the extra info that fields have, such as a default widget to display the field? (Obviously if the fields are computed there are no validators.)
mdipierro
Nov 1, 2009, 12:39:25 AM11/1/09
to web2py-users
I have done it. Post it soon. Yet, it is append.
mdipierro
Nov 1, 2009, 12:40:05 AM11/1/09
to web2py-users
They only have values. widgets and validators in web2py are only for
input.
On Oct 31, 3:45 pm, Joe Barnhart <joe.barnh...@gmail.com> wrote:
> I admit I'm not "up" on virtual fields. I didn't notice them when they were
> added. I'm wondering if they carry the extra info that fields have, such as
> a default widget to display the field? (Obviously if the fields are
> computed there are no validators.)
>
input.
On Oct 31, 3:45 pm, Joe Barnhart <joe.barnh...@gmail.com> wrote:
> I admit I'm not "up" on virtual fields. I didn't notice them when they were
> added. I'm wondering if they carry the extra info that fields have, such as
> a default widget to display the field? (Obviously if the fields are
> computed there are no validators.)
>
mr.freeze
Nov 1, 2009, 4:01:39 PM11/1/09
to web2py-users
Tested and working. It threw me off because the virtual fields don't
show up in BEAUTIFY(rows) for some reason. Thanks.
show up in BEAUTIFY(rows) for some reason. Thanks.
mdipierro
Nov 1, 2009, 4:25:16 PM11/1/09
to web2py-users
True they do not. That is a complicated matter.
BEAUTIFY tries serialize rows by calling rows.xml() which calls
SQLTABLE(rows) and that only display rows.colnames where colnames are
returned by the DB, not computed.
I am not convinced this behavior should be changed since there is no
way to enable/disable columns potentially associated to virtual fields
and there are going to be more virtual fields than one wants to
display.
Massimo
BEAUTIFY tries serialize rows by calling rows.xml() which calls
SQLTABLE(rows) and that only display rows.colnames where colnames are
returned by the DB, not computed.
I am not convinced this behavior should be changed since there is no
way to enable/disable columns potentially associated to virtual fields
and there are going to be more virtual fields than one wants to
display.
Massimo
mr.freeze
Nov 1, 2009, 4:48:47 PM11/1/09
to web2py-users
That makes sense. Do you think virtual fields should have a represent
attribute?
attribute?
mdipierro
Nov 1, 2009, 5:26:50 PM11/1/09
to web2py-users
I think no. They are their own representation.
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