Migrations

rubyonrails-talk
1

the VERSION value at in rake db:migrate VERSION=[versionNumber] is the migration number right? for instance lets say I have 3 models generated in this respective order albums, users, and reviews. If I do "rake db:migrate VERSION=0", it will delete the data and existence of all three tables....if I do VERSION=1, it will delete the existance/ data of users and reviews etc etc...

So my problem is I rolled back to VERSION=0, added a column to Review in the migration file, and migrated again. For some reason rails didn't acknowledge the change and the table indecies are still the same.

So my before I rolled back to version 0:

class CreateReviews < ActiveRecord::Migration   def self.up     create_table :reviews, :force => true do |t|       t.text :productReview       t.string :product       t.string :productCreator

      t.timestamps     end

  end

  def self.down     drop_table :reviews   end end

I then put in a coloumn called album_id

class CreateReviews < ActiveRecord::Migration   def self.up     create_table :reviews, :force => true do |t|       t.text :productReview       t.string :product       t.string :productCreator       t.integer :album_id       t.timestamps     end

  end

  def self.down     drop_table :reviews   end end

Rand db:migrate and checked my structure in the console and it's still the previous version without album_id....

Any thoughts?

2

the VERSION value at in rake db:migrate VERSION=[versionNumber] is the migration number right? for instance lets say I have 3 models generated in this respective order albums, users, and reviews. If I do "rake db:migrate VERSION=0", it will delete the data and existence of all three tables....if I do VERSION=1, it will delete the existance/ data of users and reviews etc etc...

So my problem is I rolled back to VERSION=0, added a column to Review in the migration file, and migrated again. For some reason rails didn't acknowledge the change and the table indecies are still the same.

So my before I rolled back to version 0:

class CreateReviews < ActiveRecord::Migration   def self.up     create_table :reviews, :force => true do |t|       t.text :productReview       t.string :product       t.string :productCreator

      t.timestamps     end

  end

  def self.down     drop_table :reviews   end end

I then put in a coloumn called album_id

class CreateReviews < ActiveRecord::Migration   def self.up     create_table :reviews, :force => true do |t|       t.text :productReview       t.string :product       t.string :productCreator       t.integer :album_id       t.timestamps     end

  end

  def self.down     drop_table :reviews   end end

Rand db:migrate and checked my structure in the console and it's still the previous version without album_id....

Any thoughts?

3

Craig,

Yeah that sounds more feasible rather than migrating down…I can definitely confirm VERSION=0 will drop the table though because when try to load the structure in the console it throws me an error.

What would be the syntax to just add a change(thus adding a new migration then)

I want to add t.intger :album_id. I’m assuming it’s a command at the command line that will product and 004 migration file?

Jon

4

I’m sorry, it doesn’t throw me an error, it says Review(Table doesn’t exist)

5

Craig,

Yeah that sounds more feasible rather than migrating down...I can definitely confirm VERSION=0 will drop the table though because when try to load the structure in the console it throws me an error.

What would be the syntax to just add a change(thus adding a new migration then)

I want to add t.intger :album_id. I'm assuming it's a command at the command line that will product and 004 migration file?

6

ok thanks, but how do you actually generate that particular migrations file from the command line?, ie it would be 004_something

7

ok thanks, but how do you actually generate that particular migrations file from the command line?, ie it would be 004_something

8

thanks craig,

I was able to generate the file w/the command and I added the “add_column” code. When I do my migrate I can see rail iteratively compiling the files and I see the

4 add_column(:reviews, :album_id, :integer)

->.2970s 4 AddAlbumIdToReviews: migrated (0.3120s)

which means that’s it’s been migrated. But when i look at my Review structure in the console window the it still doesn’t show up…any more thoughts?

9

thanks craig,

I was able to generate the file w/the command and I added the "add_column" code. When I do my migrate I can see rail iteratively compiling the files and I see the

4 add_column(:reviews, :album_id, :integer) ->.2970s 4 AddAlbumIdToReviews: migrated (0.3120s)

which means that's it's been migrated. But when i look at my Review structure in the console window the it still doesn't show up...any more thoughts?

Just curious: how are you viewing the structure via the console? Are you looking at an already loaded instance via the ruby console, like:

review = Review.find(:first) review

Or are you viewing it via your db's console?

10

I’m just loading it like this:

Review Review(id: integer, productReview:text, product: string, productCreator: string, created_at: datetime, updated_at: datetime)

It’s strange, I added an identical id to another structure called Album, well I added “review_id”, and it worked out fine.

11

Have you tried restarting the console after you ran the migration?

12

you know that might be a good idea…

13

Craig,

It worked. Thank you…please excuse me while I go shoot myself for not trying that already. It’s funny restarting the console has worked in some instances like this before…but I was lazy and did “reload!” instead. Rails is funny…

Thanks again

Jon