thr3ads.net - Rails - Code to update all fields and columns in table with specific value? [Dec 2010]

If this information is useful, please help other people find it:
Share via:

David Kahn

2010-Dec-30 17:10 UTC

Code to update all fields and columns in table with specific value?

I just created a migration which changes my default values for string and
text fields to empty string rather than nil.

I need to update all existing records where a string or text field in this
table is nil. This is what I am trying but just curious if there is a better
way, I don''t quite have it working and just seems like there might be a
better way:

# model I am updating is TravelCard
    travel_card_columns_hash = TravelCard.columns_hash
    TravelCard.all.each do |travel_card|
      travel_card_columns_hash.keys.each do |key|
        if travel_card_columns_hash[key].type.downcase ==
''string'' ||
travel_card_columns_hash[key].type.downcase == ''text''
          if !eval(''travel_card.key'')
            travel_card.key = ''''
          end
        end
      end
    end

-- 
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.

Marnen Laibow-Koser

2010-Dec-30 17:17 UTC

head link

Re: Code to update all fields and columns in table with specific value?

David Kahn wrote in post #971487:> I just created a migration which changes my default values for string
> and
> text fields to empty string rather than nil.
Why?
>
> I need to update all existing records where a string or text field in
> this
> table is nil.
Why?
> This is what I am trying but just curious if there is a
> better
> way, I don''t quite have it working and just seems like there might
be a
> better way:
>
> # model I am updating is TravelCard
>     travel_card_columns_hash = TravelCard.columns_hash
>     TravelCard.all.each do |travel_card|
>       travel_card_columns_hash.keys.each do |key|
>         if travel_card_columns_hash[key].type.downcase ==
''string'' ||
> travel_card_columns_hash[key].type.downcase == ''text''
>           if !eval(''travel_card.key'')
>             travel_card.key = ''''
>           end
>         end
>       end
>     end
There probably is.  But I confess to not seeing any point to doing this 
in the first place.  What are you trying to achieve?

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

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

-- 
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.

Philip Hallstrom

2010-Dec-30 17:29 UTC

head link

Re: Code to update all fields and columns in table with specific value?

On Dec 30, 2010, at 9:10 AM, David Kahn wrote:
> I just created a migration which changes my default values for string and
text fields to empty string rather than nil.
> 
> I need to update all existing records where a string or text field in this
table is nil. This is what I am trying but just curious if there is a better
way, I don''t quite have it working and just seems like there might be a
better way:
Do it in the migration itself...  as sql... it''s simpler, it''s
self contained, it''s right there along side the code that changes the
default...

%w[text_field1 text_field2].each do |field|
  TravelCard.update_all("#{field} = ''''",
"#{field} IS NULL")
end

The only reason not to do the above is if you can''t make the change at
the same time you alter the defaults.

But like Marnen said, I''d take a good look at why you think this change
is necessary...  There are some benefits to being able to distinguish between
empty strings and null values...

-philip



> # model I am updating is TravelCard
>     travel_card_columns_hash = TravelCard.columns_hash
>     TravelCard.all.each do |travel_card|
>       travel_card_columns_hash.keys.each do |key| 
>         if travel_card_columns_hash[key].type.downcase ==
''string'' || travel_card_columns_hash[key].type.downcase ==
''text''
>           if !eval(''travel_card.key'')
>             travel_card.key = ''''
>           end
>         end
>       end
>     end
> 
> -- 
> You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
> To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
> To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
> For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.
-- 
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.

David Kahn

2010-Dec-30 17:42 UTC

head link

Re: Code to update all fields and columns in table with specific value?

On Thu, Dec 30, 2010 at 11:29 AM, Philip Hallstrom
<philip-LSG90OXdqQE@public.gmane.org> wrote:
>
> On Dec 30, 2010, at 9:10 AM, David Kahn wrote:
>
> > I just created a migration which changes my default values for string
and
> text fields to empty string rather than nil.
> >
> > I need to update all existing records where a string or text field in
> this table is nil. This is what I am trying but just curious if there is a
> better way, I don''t quite have it working and just seems like
there might be
> a better way:
>
> Do it in the migration itself...  as sql... it''s simpler,
it''s self
> contained, it''s right there along side the code that changes the
default...
>
> %w[text_field1 text_field2].each do |field|
>  TravelCard.update_all("#{field} = ''''",
"#{field} IS NULL")
> end
>
> The only reason not to do the above is if you can''t make the
change at the
> same time you alter the defaults.
>
> But like Marnen said, I''d take a good look at why you think this
change is
> necessary...  There are some benefits to being able to distinguish between
> empty strings and null values...
>
Ok, actually I would like your ideas. The issue started with a problem in a
view where I am using the field value to determine what css class I use on
an element. Things were fine until I got a nil value out of the db because
of course field#downcase fails if nil. So the conclusion I came to is that I
dont want to have to add disgusting stuff to the view like:

<span
class="gateway_selector_side_highlight_<%@travel_card.dominant_occiput.downcase
if @travel_card.dominant_occiput
%>"></span>

and rather have

<span
class="gateway_selector_side_highlight_<%@travel_card.dominant_occiput.downcase
%>"></span>

So that is where I realized I could either write logic in the model (more
work) or set a default db value which would seem less work. I am not in love
with the idea of default db values, never really have been, but it seemed
like the best place. Basically in this case nil or empty string mean the
same to me.

Is there a better option?

Thinking aloud I guess I could add a helper method to handle the value
generation... which now in retrospect does seem easier than this kind of
disgusting db migration

> -philip
>
>
>
>
> > # model I am updating is TravelCard
> >     travel_card_columns_hash = TravelCard.columns_hash
> >     TravelCard.all.each do |travel_card|
> >       travel_card_columns_hash.keys.each do |key|
> >         if travel_card_columns_hash[key].type.downcase ==
''string'' ||
> travel_card_columns_hash[key].type.downcase == ''text''
> >           if !eval(''travel_card.key'')
> >             travel_card.key = ''''
> >           end
> >         end
> >       end
> >     end
> >
> > --
> > You received this message because you are subscribed to the Google
Groups
> "Ruby on Rails: Talk" group.
> > To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
> > To unsubscribe from this group, send email to
>
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org<rubyonrails-talk%2Bunsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org>
> .
> > For more options, visit this group at
> http://groups.google.com/group/rubyonrails-talk?hl=en.
>
> --
> You received this message because you are subscribed to the Google Groups
> "Ruby on Rails: Talk" group.
> To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
> To unsubscribe from this group, send email to
>
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org<rubyonrails-talk%2Bunsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org>
> .
> For more options, visit this group at
> http://groups.google.com/group/rubyonrails-talk?hl=en.
>
>
-- 
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.

Philip Hallstrom

2010-Dec-30 17:59 UTC

head link

Re: Code to update all fields and columns in table with specific value?

> > I just created a migration which changes my default values for string
and text fields to empty string rather than nil.
> >
> > I need to update all existing records where a string or text field in
this table is nil. This is what I am trying but just curious if there is a
better way, I don''t quite have it working and just seems like there
might be a better way:
> 
> Do it in the migration itself...  as sql... it''s simpler,
it''s self contained, it''s right there along side the code that
changes the default...
> 
> %w[text_field1 text_field2].each do |field|
>  TravelCard.update_all("#{field} = ''''",
"#{field} IS NULL")
> end
> 
> The only reason not to do the above is if you can''t make the
change at the same time you alter the defaults.
> 
> But like Marnen said, I''d take a good look at why you think this
change is necessary...  There are some benefits to being able to distinguish
between empty strings and null values...
> 
> Ok, actually I would like your ideas. The issue started with a problem in a
view where I am using the field value to determine what css class I use on an
element. Things were fine until I got a nil value out of the db because of
course field#downcase fails if nil. So the conclusion I came to is that I dont
want to have to add disgusting stuff to the view like:
> 
> <span class="gateway_selector_side_highlight_<%=
@travel_card.dominant_occiput.downcase if @travel_card.dominant_occiput
%>"></span>
> 
> and rather have 
>  
> <span class="gateway_selector_side_highlight_<%=
@travel_card.dominant_occiput.downcase %>"></span>
> 
> So that is where I realized I could either write logic in the model (more
work) or set a default db value which would seem less work. I am not in love
with the idea of default db values, never really have been, but it seemed like
the best place. Basically in this case nil or empty string mean the same to me.
> 
> Is there a better option?
> 
> Thinking aloud I guess I could add a helper method to handle the value
generation... which now in retrospect does seem easier than this kind of
disgusting db migration
Yep!  Helper method for the win :)

-philip

> 
> -philip
> 
> 
> 
> 
> > # model I am updating is TravelCard
> >     travel_card_columns_hash = TravelCard.columns_hash
> >     TravelCard.all.each do |travel_card|
> >       travel_card_columns_hash.keys.each do |key|
> >         if travel_card_columns_hash[key].type.downcase ==
''string'' || travel_card_columns_hash[key].type.downcase ==
''text''
> >           if !eval(''travel_card.key'')
> >             travel_card.key = ''''
> >           end
> >         end
> >       end
> >     end
> >
> > --
> > You received this message because you are subscribed to the Google
Groups "Ruby on Rails: Talk" group.
> > To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
> > To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
> > For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.
> 
> --
> You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
> To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
> To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe@googlegroups.com.
> For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.
> 
> 
> 
> -- 
> You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
> To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
> To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe@googlegroups.com.
> For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.
-- 
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.

David Kahn

2010-Dec-30 18:03 UTC

head link

Re: Code to update all fields and columns in table with specific value?

On Thu, Dec 30, 2010 at 11:59 AM, Philip Hallstrom
<philip-LSG90OXdqQE@public.gmane.org> wrote:
> > I just created a migration which changes my default values for string
and
>> text fields to empty string rather than nil.
>> >
>> > I need to update all existing records where a string or text field
in
>> this table is nil. This is what I am trying but just curious if there
is a
>> better way, I don''t quite have it working and just seems like
there might be
>> a better way:
>>
>> Do it in the migration itself...  as sql... it''s simpler,
it''s self
>> contained, it''s right there along side the code that changes
the default...
>>
>> %w[text_field1 text_field2].each do |field|
>>  TravelCard.update_all("#{field} = ''''",
"#{field} IS NULL")
>> end
>>
>> The only reason not to do the above is if you can''t make the
change at the
>> same time you alter the defaults.
>>
>> But like Marnen said, I''d take a good look at why you think
this change is
>> necessary...  There are some benefits to being able to distinguish
between
>> empty strings and null values...
>>
>
> Ok, actually I would like your ideas. The issue started with a problem in a
> view where I am using the field value to determine what css class I use on
> an element. Things were fine until I got a nil value out of the db because
> of course field#downcase fails if nil. So the conclusion I came to is that
I
> dont want to have to add disgusting stuff to the view like:
>
> <span class="gateway_selector_side_highlight_<%>
@travel_card.dominant_occiput.downcase if @travel_card.dominant_occiput
> %>"></span>
>
> and rather have
>
> <span class="gateway_selector_side_highlight_<%>
@travel_card.dominant_occiput.downcase %>"></span>
>
> So that is where I realized I could either write logic in the model (more
> work) or set a default db value which would seem less work. I am not in
love
> with the idea of default db values, never really have been, but it seemed
> like the best place. Basically in this case nil or empty string mean the
> same to me.
>
> Is there a better option?
>
> Thinking aloud I guess I could add a helper method to handle the value
> generation... which now in retrospect does seem easier than this kind of
> disgusting db migration
>
>
> Yep!  Helper method for the win :)
>
Yeah, what was I thinking :) Like a flashback to my ASP.NET/SqlServer days,
must be PTSD.

>
> -philip
>
>
>
>> -philip
>>
>>
>>
>>
>> > # model I am updating is TravelCard
>> >     travel_card_columns_hash = TravelCard.columns_hash
>> >     TravelCard.all.each do |travel_card|
>> >       travel_card_columns_hash.keys.each do |key|
>> >         if travel_card_columns_hash[key].type.downcase ==
''string'' ||
>> travel_card_columns_hash[key].type.downcase == ''text''
>> >           if !eval(''travel_card.key'')
>> >             travel_card.key = ''''
>> >           end
>> >         end
>> >       end
>> >     end
>> >
>> > --
>> > You received this message because you are subscribed to the Google
>> Groups "Ruby on Rails: Talk" group.
>> > To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
>> > To unsubscribe from this group, send email to
>>
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org<rubyonrails-talk%2Bunsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org>
>> .
>> > For more options, visit this group at
>> http://groups.google.com/group/rubyonrails-talk?hl=en.
>>
>> --
>> You received this message because you are subscribed to the Google
Groups
>> "Ruby on Rails: Talk" group.
>> To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
>> To unsubscribe from this group, send email to
>>
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org<rubyonrails-talk%2Bunsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org>
>> .
>> For more options, visit this group at
>> http://groups.google.com/group/rubyonrails-talk?hl=en.
>>
>>
>
> --
> You received this message because you are subscribed to the Google Groups
> "Ruby on Rails: Talk" group.
> To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
> To unsubscribe from this group, send email to
>
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
> For more options, visit this group at
> http://groups.google.com/group/rubyonrails-talk?hl=en.
>
>
>  --
> You received this message because you are subscribed to the Google Groups
> "Ruby on Rails: Talk" group.
> To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
> To unsubscribe from this group, send email to
>
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org<rubyonrails-talk%2Bunsubscribe-/JYPxA39Uh5TLH3MbocFFw@public.gmane.org>
> .
> For more options, visit this group at
> http://groups.google.com/group/rubyonrails-talk?hl=en.
>
-- 
You received this message because you are subscribed to the Google Groups
"Ruby on Rails: Talk" group.
To post to this group, send email to
rubyonrails-talk-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
To unsubscribe from this group, send email to
rubyonrails-talk+unsubscribe-/JYPxA39Uh5TLH3MbocFF+G/Ez6ZCGd0@public.gmane.org
For more options, visit this group at
http://groups.google.com/group/rubyonrails-talk?hl=en.

Rails - Dec 2010 - Code to update all fields and columns in table with specific value?

Code to update all fields and columns in table with specific value?

Re: Code to update all fields and columns in table with specific value?

Re: Code to update all fields and columns in table with specific value?

Re: Code to update all fields and columns in table with specific value?

Re: Code to update all fields and columns in table with specific value?

Re: Code to update all fields and columns in table with specific value?