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author | Vijay Dev <vijaydev.cse@gmail.com> | 2011-08-03 19:11:22 +0530 |
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committer | Xavier Noria <fxn@hashref.com> | 2011-08-04 16:41:30 -0700 |
commit | b3719ee7ed4693c782087c56c2ba5984a473deb7 (patch) | |
tree | 4182edb49c80bd89601f9a6e691db5f63f0fa58f | |
parent | 9e1a27a0ac4ef246079ac6f61f5b5916c68d0497 (diff) | |
download | rails-b3719ee7ed4693c782087c56c2ba5984a473deb7.tar.gz rails-b3719ee7ed4693c782087c56c2ba5984a473deb7.tar.bz2 rails-b3719ee7ed4693c782087c56c2ba5984a473deb7.zip |
fixed incorrect tags
-rw-r--r-- | railties/guides/source/migrations.textile | 32 |
1 files changed, 16 insertions, 16 deletions
diff --git a/railties/guides/source/migrations.textile b/railties/guides/source/migrations.textile index e51ee0f535..7b501807d6 100644 --- a/railties/guides/source/migrations.textile +++ b/railties/guides/source/migrations.textile @@ -477,7 +477,7 @@ Several methods are provided that allow you to control all this: For example, this migration -<pre> +<ruby> class CreateProducts < ActiveRecord::Migration def change suppress_messages do @@ -496,7 +496,7 @@ class CreateProducts < ActiveRecord::Migration end end end -</pre> +</ruby> generates the following output @@ -525,7 +525,7 @@ Bob goes on vacation. Alice creates a migration for the +products+ table which adds a new column and initializes it. She also adds a validation to the Product model for the new column. -<pre> +<ruby> # db/migrate/20100513121110_add_flag_to_product.rb class AddFlagToProduct < ActiveRecord::Migration @@ -534,19 +534,19 @@ class AddFlagToProduct < ActiveRecord::Migration Product.all.each { |f| f.update_attributes!(:flag => 'false') } end end -</pre> +</ruby> -<pre> +<ruby> # app/model/product.rb class Product < ActiveRecord::Base validates_presence_of :flag end -</pre> +</ruby> Alice adds a second migration which adds and initializes another column to the +products+ table and also adds a validation to the Product model for the new column. -<pre> +<ruby> # db/migrate/20100515121110_add_fuzz_to_product.rb class AddFuzzToProduct < ActiveRecord::Migration @@ -555,16 +555,16 @@ class AddFuzzToProduct < ActiveRecord::Migration Product.all.each { |f| f.update_attributes! :fuzz => 'fuzzy' } end end -</pre> +</ruby> -<pre> +<ruby> # app/model/product.rb class Product < ActiveRecord::Base validates_presence_of :flag validates_presence_of :fuzz end -</pre> +</ruby> Both migrations work for Alice. @@ -575,12 +575,12 @@ Bob comes back from vacation and: The migration crashes because when the model attempts to save, it tries to validate the second added column, which is not in the database when the _first_ migration runs. -<pre> +<plain> rake aborted! An error has occurred, this and all later migrations canceled: undefined method `fuzz' for #<Product:0x000001049b14a0> -</pre> +</plain> A fix for this is to create a local model within the migration. This keeps rails from running the validations, so that the migrations run to completion. @@ -588,7 +588,7 @@ When using a faux model, it's a good idea to call +Product.reset_column_informat If Alice had done this instead, there would have been no problem: -<pre> +<ruby> # db/migrate/20100513121110_add_flag_to_product.rb class AddFlagToProduct < ActiveRecord::Migration @@ -600,9 +600,9 @@ class AddFlagToProduct < ActiveRecord::Migration Product.all.each { |f| f.update_attributes!(:flag => false) } end end -</pre> +</ruby> -<pre> +<ruby> # db/migrate/20100515121110_add_fuzz_to_product.rb class AddFuzzToProduct < ActiveRecord::Migration @@ -614,7 +614,7 @@ class AddFuzzToProduct < ActiveRecord::Migration Product.all.each { |f| f.update_attributes! :fuzz => 'fuzzy' } end end -</pre> +</ruby> h3. Schema Dumping and You |