Rails - Apr 2006 - adding primary_key to join table using migrations

Hi list,

My tag_question_user join table is not currently a full-blown model. It
doesn''t have a primary key - just tag_id, question_id, and user_id.

I now want to add a primary key to this model (because I want to add a
"description" column as well so users can describe the tag.

I''m not sure how to add this using migrations.

Here is what I have:
class AddNotesToTags < ActiveRecord::Migration
  def self.up
      add_column :tags_questions_users, "id", :primary_key
      add_column :tags_questions_users, "description", :string, :limit
=>
80, :null => false
  end

  def self.down
      remove_column :tags_questions_users, "id"
      remove_column :tags_questions_users, "description"
  end
end

That''s giving me this error:

Mysql::Error: #42000You have an error in your SQL syntax; check the manual
that
corresponds to your MySQL server version for the right syntax to use near
''''
at
line 1: ALTER TABLE tags_questions_users ADD id

Any suggestions?

Thanks,

Steve
http://www.smarkets.net
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Hi Steve,

Did you ever find a solution to this?  We''re having the same problem.  
As far as I can see the mysql adapter isn''t set up to handle the 
:primary_key type.

I found a patch for Postgre:

http://dev.rubyonrails.org/ticket/3735

Looks like this might be fixed in 1.2

CHEERS> SAM


Steve Odom wrote:
> Hi list,
>
> My tag_question_user join table is not currently a full-blown model. 
> It doesn''t have a primary key - just tag_id, question_id, and
user_id.
>
> I now want to add a primary key to this model (because I want to add a 
> "description" column as well so users can describe the tag.
>
> I''m not sure how to add this using migrations.
>
> Here is what I have:
> class AddNotesToTags < ActiveRecord::Migration
>   def self.up
>       add_column :tags_questions_users, "id", :primary_key
>       add_column :tags_questions_users, "description", :string,
:limit
> => 80, :null => false
>   end
>
>   def self.down
>       remove_column :tags_questions_users, "id"
>       remove_column :tags_questions_users, "description"
>   end
> end
>
> That''s giving me this error:
>
> Mysql::Error: #42000You have an error in your SQL syntax; check the 
> manual that
> corresponds to your MySQL server version for the right syntax to use 
> near '''' at
> line 1: ALTER TABLE tags_questions_users ADD id
>
> Any suggestions?
>
> Thanks,
>
> Steve
> http://www.smarkets.net
>
>------------------------------------------------------------------------
>
>_______________________________________________
>Rails mailing list
>Rails@lists.rubyonrails.org
>http://lists.rubyonrails.org/mailman/listinfo/rails
>  
>

I''m also looking for some way to drop a primary key, but my first
attempt:

    remove_index :workspaces_discussions, :primary_key

has failed miserably:

Mysql::Error: Can''t DROP
''workspaces_discussions_primary_key_index'';
check that
column/key exists: DROP INDEX workspaces_discussions_primary_key_index 
ON worksp
aces_discussions

Many thanks for any suggestions.

CHEERS> SAM

Sam Joseph wrote:
> Hi Steve,
>
> Did you ever find a solution to this?  We''re having the same
problem.
> As far as I can see the mysql adapter isn''t set up to handle the 
> :primary_key type.
>
> I found a patch for Postgre:
>
> http://dev.rubyonrails.org/ticket/3735
>
> Looks like this might be fixed in 1.2
>
> CHEERS> SAM
>
>
> Steve Odom wrote:
>
>> Hi list,
>>
>> My tag_question_user join table is not currently a full-blown model. 
>> It doesn''t have a primary key - just tag_id, question_id, and
user_id.
>>
>> I now want to add a primary key to this model (because I want to add 
>> a "description" column as well so users can describe the tag.
>>
>> I''m not sure how to add this using migrations.
>>
>> Here is what I have:
>> class AddNotesToTags < ActiveRecord::Migration
>>   def self.up
>>       add_column :tags_questions_users, "id", :primary_key
>>       add_column :tags_questions_users, "description",
:string,
>> :limit => 80, :null => false
>>   end
>>
>>   def self.down
>>       remove_column :tags_questions_users, "id"
>>       remove_column :tags_questions_users, "description"
>>   end
>> end
>>
>> That''s giving me this error:
>>
>> Mysql::Error: #42000You have an error in your SQL syntax; check the 
>> manual that
>> corresponds to your MySQL server version for the right syntax to use 
>> near '''' at
>> line 1: ALTER TABLE tags_questions_users ADD id
>>
>> Any suggestions?
>>
>> Thanks,
>>
>> Steve
>> http://www.smarkets.net
>>
>>
------------------------------------------------------------------------
>>
>> _______________________________________________
>> Rails mailing list
>> Rails@lists.rubyonrails.org
>> http://lists.rubyonrails.org/mailman/listinfo/rails
>>  
>>
>
> _______________________________________________
> Rails mailing list
> Rails@lists.rubyonrails.org
> http://lists.rubyonrails.org/mailman/listinfo/rails
>
>

My table primary key is "DATE" and not "ID"

now When I use mymodel.find("mydate") it''s returns that my
table does
not have a column "id"
ok...

now how to search by DATE and not "id" ?

tks.

Hi Fernando,

Fernando wrote:
> My table primary key is "DATE" and not "ID"
>
> now When I use mymodel.find("mydate") it''s returns that
my table does not
> have a column "id"
> ok...
>
> now how to search by DATE and not "id" ?
>
Rails is built on top of ActiveRecord which assumes the primary key is a 
"meaningless" integer.  Simply add a date field (I don''t
think you can name
it just ''date'', but you should check the wiki for reserved /
magic words).
In Rails, assuming your date column is named ''mydate'',
you''ll use

mymodel.find(:first, :conditions => ["mydate = ?", mydate])

hth,
Bill

On 7/6/06, Fernando <fernando@setti.com.br> wrote:
> My table primary key is "DATE" and not "ID"
>
> now When I use mymodel.find("mydate") it''s returns that
my table does
> not have a column "id"
> ok...
>
> now how to search by DATE and not "id" ?
You need to override AR default with set_primary_key ''date'' in
your
Model. AR assumes the primary key is called "id".
If you are not using legacy schemas, best practice is however using
Integer primary keys.
Cheers.
-- 
francesco levorato aka flevour
http://www.flevour.net/