I have created a function in model that retrieves the idea of creating
it uisng this link:
The aim of the function is to calculate the following formula, provided
that all are fields in the table:
quantity_sold = receive + deliver
This is how my model looks like:
Class Iteminfo < ActiveRecord::Base
attr_accessor :receive, :deliver
before_create :calculate_quantity_sold
private
def calculate_quantity_sold
self.quantity_sold = receive.to_i + deliver.to_i
end
end
Now, when I enter values for the “deliver” and “receive” fields, say:
receive = 10
deliver = 10
I get the following value for “quantity_sold” —> 20
Where is the problem?
The problem is that when I enter the values on the form for the
“receive” and “deliver” fields, and then hit the “Create” buttom, in the
“show” page, I get a “20” beside the “quantity_sold” field shown and
EMPTY fields for “deliver” and “receive”.
The other problem is that when I for example want to see the data in my
table using Firefoxe’s SQLite Manager I do NOT get any data shown
although I can see it in the form “index” page.
What is the problem here?
Thanks.
Regarding the fields in SQL Manager, I found that I was browsing the
wrong database.
And, in my model in order to get values for “receive” amd “deliver” I
had to remove this line:
attr_accessor :receive, :deliver
The function should bbe
Def quantity_sold
Delivered_item + item_price
End
Then call quantity_sold.
Removing attr_accesible is a very bat idea.
2010/9/23, Abder-Rahman A. [email protected]:
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On 23 September 2010 10:47, radhames brito [email protected]
topposted again without any sign of trimming:
The function should bbe
Def quantity_sold
Delivered_item + item_price
End
If you’re going to write example code, please take the time to make
sure it might even work… you should be aware of the case-sensitivity
of Ruby.
What on earth does “item_price” have to do with quantity sold? Where
has the OP mentioned that? And infact, where has “Delivered_item” come
from? Can I just check that you replied to the right message?
Then call quantity_sold.
The OP has stated he wants to store the quantity_sold in the DB - how
will this method help achieve that?
Removing attr_accesible is a very bat idea.
He hasn’t said anything about removing attr_accesible - he’s removed
the attr_accessor definitions - which is correct if he’s got fields
for those values he doesn’t need to create accessors for them.
The question might be to check with the OP whether he really needs
to store the calculated value, or whether it would just be easier to
have a method (similar to the one you proposed, but using the correct
calculation) to return the value when asked. I suppose it depends
whether he’s doing a lot of DB queries on the quantity_sold - in which
case it might be better to have it in the DB, of if it’s just for use
in views, then possible a (memoized) calculated value might be
“better” to prevent any risk of the values getting out-of sync
(nothing worse than someone running an update on the db and changing
values without updating the calculated values…)
ok now im awake and on my pc , yes my reply made no sense, the problem
is
that i cant trimm comments from the phone and i cant see the op as i
reply,
and since i had just woke up , i couldnt quite remember what the op was
about as i reply.
I wont repeat that.
Sorry im replying from i new phone and is 5:00 am where i live , i
should have waited until i get to my pc and drink some coffe
2010/9/23, Michael P. [email protected]:
sure it might even work… you should be aware of the case-sensitivity
Removing attr_accesible is a very bat idea.
case it might be better to have it in the DB, of if it’s just for use
[email protected].
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.
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Enviado desde mi dispositivo móvil