Question about ActiveRecord

[laurent]

Hi

I have a quick creation form (in a form) : the displayed fields
correspond only to some of the attributes of the corresponding model.

In my controller , create action :
esaily, i would like to use the :
@user = User.new(params[:user])
if @user.save
#success
else
#failure
end

But i would like to know if the generated SQL statement for creation
will include all the columns of the mapped table by my model (i think
yes…)

Is there a tip to only save fields that are not empty for example or
better, only certain named fields:

The table has many columns : col1, col2, col3, col4, …, colN

I’d like to have an INSERT statement like this one :
INSERT INTO Users(col1, col2, col3, col4) VALUES (‘a’, ‘b’, ‘c’, ‘d’)
– Others columns : col5…colN are not concerned by this INSERT

Thanks

Laurent

[laurent]

Laurent,

Next to what Pat wrote, you should take the habit of looking at the
/log/developement.log
file.
You’ll see there 1/the parameters passed to the action, and 2/ the
executed SQL commands.
The logs are an invaluable resource.

Alain

blog.ravet.com

[laurent]

On 5/10/07, Laurent [email protected] wrote:

#success

If you only pass columns col1, col2, col3, and col4 to
update_attributes, then those are the only ones that are going to be
updated in the db.

Pat

[laurent]

Laurent wrote:

Then , the SQL statement (INSERT) i see, includes all the columns…too
bad.
…
In Oracle, with views on top of a single Table, you can do
Inserts…But, this insert will fail on virtual columns.
That’s why i need to filter the columns in my INSERT statement…

Check out the attr_readonly patch:
http://dev.rubyonrails.org/ticket/6896

–
We develop, watch us RoR, in numbers too big to ignore.

[laurent]

Mark,

Are you sure it answers my issue…
Because i see on the page for your Patch, it’s related to
counter_cache…

[PATCH] counter_cache value gets overwritten

Laurent

[laurent]

Yes Alain, it is what i do since i began to develop (with RoR, or as
for more longer time with Java )

When checking the logs i see the generated SQL statement…

I do in my controller :
suivi = Vgisuivi.new do |s|
s.update_attribute(‘id’, @sequence.to_i)
s.update_attribute(‘role_id’, params[:role_id])
s.update_attribute(‘objet_id’, params[:objet_id])
s.update_attribute(‘user_id’ , params[:user_id])
end

Then , teh SQL statement (INSET) i see, includes all the columns…too
bad.

In fact i need to do this because
We work on a legacy database …in Oracle
On top of the tables we do some views, more closer to RoR conventions
(naming pk by id, etc etc…)
Some of these views have virtual columns (i.e the label of a code,
coming from the call of a PL/SQL function)

In Oracle, with views on top of a single Table, you can do
Inserts…But, this insert will fail on virtual columns.
That’s why i need to filter the columns in my INSERT statement…

L

[laurent]

Laurent wrote:

Are you sure it answers my issue…
Because i see on the page for your Patch, it’s related to
counter_cache…

[PATCH] counter_cache value gets overwritten

The attr_readonly patch is a general solution for restricting
the fields included in database updates, but all fields are still
included in database inserts (ActiveRecord new_record? = true).
So it may not be a total solution to your problem.

Mark

–
We develop, watch us RoR, in numbers too big to ignore.