Rails - Oct 2009 - Inserting multiple records from one table (model) to another

Hello all,
I''ve been getter better with Rails but I''m still just
learning.

Here''s what I have.
I have one table (imports) and I read in a csv into this table.
After doing some preliminary editing to each record I wish to insert all
records into another table (projects) in one shot.
I could create a new method in the projects controller and then call the
"create", but doesn''t that only insert one record?

I need a little clarity on this.

I know how to delete all records from a table. I wonder if it''s as
simple?

Thank you for any help.

JohnM
-- 
Posted via http://www.ruby-forum.com/.

John Mcleod wrote:
> Hello all,
> I''ve been getter better with Rails but I''m still just
learning.
> 
> Here''s what I have.
> I have one table (imports) and I read in a csv into this table.
> After doing some preliminary editing to each record I wish to insert all
> records into another table (projects) in one shot.
> I could create a new method in the projects controller and then call the
> "create", but doesn''t that only insert one record?
Yes.  In this case, if the tables have the same structure, you might 
want to use SQL''s INSERT SELECT syntax (see your DB for details).

But having two tables with identical structure is smelly.  Why not just 
use a flag and a named_scope?
> 
> I need a little clarity on this.
> 
> I know how to delete all records from a table. I wonder if it''s as
> simple?
Rails doesn''t abstract this AFAIK, in part because this is very rarely 
needed.
> 
> Thank you for any help.
> 
> JohnM
Best,
--
Marnen Laibow-Koser
http://www.marnen.org
marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org
-- 
Posted via http://www.ruby-forum.com/.

Thanks for the quick reply.
>But having two tables with identical structure is smelly.  Why not just 
> use a flag and a named_scope?
I''m not sure what you mean by this.

Yes, both tables have the identical structure but my idea is too delete 
all data from the "import" table after the insert into the
"projects"
table.  This way the user has a fresh table to get info from a csv file.

John

Marnen Laibow-Koser wrote:
> John Mcleod wrote:
>> Hello all,
>> I''ve been getter better with Rails but I''m still just
learning.
>> 
>> Here''s what I have.
>> I have one table (imports) and I read in a csv into this table.
>> After doing some preliminary editing to each record I wish to insert
all
>> records into another table (projects) in one shot.
>> I could create a new method in the projects controller and then call
the
>> "create", but doesn''t that only insert one record?
> 
> Yes.  In this case, if the tables have the same structure, you might 
> want to use SQL''s INSERT SELECT syntax (see your DB for details).
> 
> But having two tables with identical structure is smelly.  Why not just 
> use a flag and a named_scope?
> 
>> 
>> I need a little clarity on this.
>> 
>> I know how to delete all records from a table. I wonder if
it''s as
>> simple?
> 
> Rails doesn''t abstract this AFAIK, in part because this is very
rarely
> needed.
>> 
>> Thank you for any help.
>> 
>> JohnM
> 
> Best,
> --
> Marnen Laibow-Koser
> http://www.marnen.org
> marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org
-- 
Posted via http://www.ruby-forum.com/.

John Mcleod wrote:
> Thanks for the quick reply.
> 
>>But having two tables with identical structure is smelly.  Why not just 
>> use a flag and a named_scope?
> I''m not sure what you mean by this.
Then go look up named_scope -- or, in this case, default_scope.
> 
> Yes, both tables have the identical structure but my idea is too delete 
> all data from the "import" table after the insert into the
"projects"
> table.  This way the user has a fresh table to get info from a csv file.
There''s no reason to have a fresh table.  Again, just flag records as 
appropriate.

Best,
--
Marnen Laibow-Koser
http://www.marnen.org
marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org
-- 
Posted via http://www.ruby-forum.com/.

Your right.
I could not deal with the additional table.

Thanks for the insight.

John

Marnen Laibow-Koser wrote:
> John Mcleod wrote:
>> Thanks for the quick reply.
>> 
>>>But having two tables with identical structure is smelly.  Why not
just
>>> use a flag and a named_scope?
>> I''m not sure what you mean by this.
> 
> Then go look up named_scope -- or, in this case, default_scope.
> 
>> 
>> Yes, both tables have the identical structure but my idea is too delete
>> all data from the "import" table after the insert into the
"projects"
>> table.  This way the user has a fresh table to get info from a csv
file.
> 
> There''s no reason to have a fresh table.  Again, just flag records
as
> appropriate.
> 
> Best,
> --
> Marnen Laibow-Koser
> http://www.marnen.org
> marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org
-- 
Posted via http://www.ruby-forum.com/.

John Mcleod wrote:
> Your right.
> I could not deal with the additional table.
You could -- it''s just poor design in most cases.
> 
> Thanks for the insight.
You''re welcome.
> 
> John
> 
>
Best,
--
Marnen Laibow-Koser
http://www.marnen.org
marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org
-- 
Posted via http://www.ruby-forum.com/.

Marnen Laibow-Koser wrote:
> 
> You could -- it''s just poor design in most cases.
> 
Most cases yes, but in some cases a parallel import table is not a bad 
thing.

If you put all your data into one table, then all the records going into 
that table have to pass all the model constraints immediately.

From John''s initial post, I read "after doing some preliminary
editing"
to imply that the records, as imported from CSV, may not satisfy all the 
constraints of the application.

It may be in his interest to keep these "dirty" records separate from 
the "clean" records so he does not have to relax any constraints on
the
mainstream application data, or complicate his existing model 
constraints by mixing a flag check into the middle of things.

Ultimately, it''ll be whatever works best for John.
-- 
Posted via http://www.ruby-forum.com/.

Ar Chron wrote:
> Marnen Laibow-Koser wrote:
>> 
>> You could -- it''s just poor design in most cases.
>> 
> 
> Most cases yes, but in some cases a parallel import table is not a bad 
> thing.
> 
> If you put all your data into one table, then all the records going into 
> that table have to pass all the model constraints immediately.
That''s true, of course.  But in that case, the tables don''t
have the
same structure, so the smell doesn''t apply.
> 
> From John''s initial post, I read "after doing some
preliminary editing"
> to imply that the records, as imported from CSV, may not satisfy all the 
> constraints of the application.
> 
> It may be in his interest to keep these "dirty" records separate
from
> the "clean" records so he does not have to relax any constraints
on the
> mainstream application data, 
You may be right.  I hadn''t thought of that from the initial 
description.
> or complicate his existing model 
> constraints by mixing a flag check into the middle of things.
default_scope is not complicated!
> 
> Ultimately, it''ll be whatever works best for John.
Best,
--
Marnen Laibow-Koser
http://www.marnen.org
marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org
-- 
Posted via http://www.ruby-forum.com/.

You are correct.
I must do some editing to incoming data before it''s
"imported" into the
"projects" table.

I''m having more problems importing data from one table to another. 
When
editing is complete, I click a button to "save" to projects table.
My button is very up front and easy.
<%= button_to "Add Records to Projects", :action =>
"addIrbProjects",
:id => import.id %>

It''s just setting up the projects Controller that has me confused.
I''m in the projects controller reading a "imports" table.


John

Ar Chron wrote:
> Marnen Laibow-Koser wrote:
>> 
>> You could -- it''s just poor design in most cases.
>> 
> 
> Most cases yes, but in some cases a parallel import table is not a bad 
> thing.
> 
> If you put all your data into one table, then all the records going into 
> that table have to pass all the model constraints immediately.
> 
> From John''s initial post, I read "after doing some
preliminary editing"
> to imply that the records, as imported from CSV, may not satisfy all the 
> constraints of the application.
> 
> It may be in his interest to keep these "dirty" records separate
from
> the "clean" records so he does not have to relax any constraints
on the
> mainstream application data, or complicate his existing model 
> constraints by mixing a flag check into the middle of things.
> 
> Ultimately, it''ll be whatever works best for John.
-- 
Posted via http://www.ruby-forum.com/.

Hello all,
I''ve been getter better with Rails but I''m still just
learning.

Here''s what I have.
I have one table (imports) and I read in a csv into this table.

I must do some preliminary editing to each record, afterwhich, I wish to
insert all records into another table (projects) in one shot.

I''ve created a button below the table

<%= button_to "Add Records to Projects", :action =>
''add_new_projects''
%>

I need a little clarity on this.

I know how to delete all records from a table. I wonder if it''s as
simple?

Thank you for any help.

JohnM
-- 
Posted via http://www.ruby-forum.com/.

John Mcleod wrote:
> Hello all,
> I''ve been getter better with Rails but I''m still just
learning.
> 
> Here''s what I have.
> I have one table (imports) and I read in a csv into this table.
> 
> I must do some preliminary editing to each record, afterwhich, I wish to
> insert all records into another table (projects) in one shot.
> 
> I''ve created a button below the table
> 
> <%= button_to "Add Records to Projects", :action =>
''add_new_projects''
> %>
> 
> I need a little clarity on this.
> 
> I know how to delete all records from a table. I wonder if it''s as
> simple?
> 
> Thank you for any help.
> 
> JohnM
You already asked this at http://www.ruby-forum.com/topic/198008 / 
http://groups.google.com/group/rubyonrails-talk/browse_thread/thread/7f09e32544d1b4f1/ede1159a796d9e64
, and got some answers.  Let''s keep further discussion to that thread.

Best,
--
Marnen Laibow-Koser
http://www.marnen.org
marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org

-- 
Posted via http://www.ruby-forum.com/.

I think you have to loop through the list saving one record each time, but I
could be wrong. If anyone''s got a better way I''d love to know
what it is. :)



On Tue, Oct 27, 2009 at 2:37 PM, John Mcleod <
rails-mailing-list-ARtvInVfO7ksV2N9l4h3zg@public.gmane.org> wrote:
>
> Hello all,
> I''ve been getter better with Rails but I''m still just
learning.
>
> Here''s what I have.
> I have one table (imports) and I read in a csv into this table.
>
> I must do some preliminary editing to each record, afterwhich, I wish to
> insert all records into another table (projects) in one shot.
>
> I''ve created a button below the table
>
> <%= button_to "Add Records to Projects", :action =>
''add_new_projects''
> %>
>
> I need a little clarity on this.
>
> I know how to delete all records from a table. I wonder if it''s as
> simple?
>
> Thank you for any help.
>
> JohnM
> --
> Posted via http://www.ruby-forum.com/.
>
> >
>
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Thank you for the reply.
I''ve been struggling with this for some time.

Recently, I have this...

- controller -
def create_csv_projects
   @imports = Import.all
   @projects = Project.all

    @imports.each { |import|
      if @projects.create!(params)
        flash[''notice''] = ''CSV projects have been
successfully created
in Projects Database.''
        redirect_to :controller => ''projects'', :action
=> ''index''
      end
    }
end

Unfortunately, it not working.

John

Jillian Galloway wrote:
> I think you have to loop through the list saving one record each time, 
> but I
> could be wrong. If anyone''s got a better way I''d love to
know what it
> is. :)
> 
> 
> 
> On Tue, Oct 27, 2009 at 2:37 PM, John Mcleod <
-- 
Posted via http://www.ruby-forum.com/.

Jillian Galloway wrote:
> I think you have to loop through the list saving one record each time, 
> but I
> could be wrong. 
And so you are.  It is never appropriate to put an SQL query inside a 
loop.
> If anyone''s got a better way I''d love to know what it 
> is. :)
>
Use something like ar-extensions if possible.  If not, then build an SQL 
query string directly.
> 
> 
> On Tue, Oct 27, 2009 at 2:37 PM, John Mcleod <
Best,
--
Marnen Laibow-Koser
http://www.marnen.org
marnen-sbuyVjPbboAdnm+yROfE0A@public.gmane.org
-- 
Posted via http://www.ruby-forum.com/.