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Diffstat (limited to 'guides/source/migrations.md')
| -rw-r--r-- | guides/source/migrations.md | 37 |
1 files changed, 21 insertions, 16 deletions
diff --git a/guides/source/migrations.md b/guides/source/migrations.md index c61ccfe94a..6742c05946 100644 --- a/guides/source/migrations.md +++ b/guides/source/migrations.md @@ -121,7 +121,7 @@ Of course, calculating timestamps is no fun, so Active Record provides a generator to handle making it for you: ```bash -$ rails generate migration AddPartNumberToProducts +$ bin/rails generate migration AddPartNumberToProducts ``` This will create an empty but appropriately named migration: @@ -138,7 +138,7 @@ followed by a list of column names and types then a migration containing the appropriate `add_column` and `remove_column` statements will be created. ```bash -$ rails generate migration AddPartNumberToProducts part_number:string +$ bin/rails generate migration AddPartNumberToProducts part_number:string ``` will generate @@ -154,7 +154,7 @@ end If you'd like to add an index on the new column, you can do that as well: ```bash -$ rails generate migration AddPartNumberToProducts part_number:string:index +$ bin/rails generate migration AddPartNumberToProducts part_number:string:index ``` will generate @@ -172,7 +172,7 @@ end Similarly, you can generate a migration to remove a column from the command line: ```bash -$ rails generate migration RemovePartNumberFromProducts part_number:string +$ bin/rails generate migration RemovePartNumberFromProducts part_number:string ``` generates @@ -188,7 +188,7 @@ end You are not limited to one magically generated column. For example: ```bash -$ rails generate migration AddDetailsToProducts part_number:string price:decimal +$ bin/rails generate migration AddDetailsToProducts part_number:string price:decimal ``` generates @@ -207,7 +207,7 @@ followed by a list of column names and types then a migration creating the table XXX with the columns listed will be generated. For example: ```bash -$ rails generate migration CreateProducts name:string part_number:string +$ bin/rails generate migration CreateProducts name:string part_number:string ``` generates @@ -231,7 +231,7 @@ Also, the generator accepts column type as `references`(also available as `belongs_to`). For instance: ```bash -$ rails generate migration AddUserRefToProducts user:references +$ bin/rails generate migration AddUserRefToProducts user:references ``` generates @@ -249,7 +249,7 @@ This migration will create a `user_id` column and appropriate index. There is also a generator which will produce join tables if `JoinTable` is part of the name: ```bash -rails g migration CreateJoinTableCustomerProduct customer product +$ bin/rails g migration CreateJoinTableCustomerProduct customer product ``` will produce the following migration: @@ -273,7 +273,7 @@ relevant table. If you tell Rails what columns you want, then statements for adding these columns will also be created. For example, running: ```bash -$ rails generate model Product name:string description:text +$ bin/rails generate model Product name:string description:text ``` will create a migration that looks like this @@ -307,7 +307,7 @@ braces. You can use the following modifiers: For instance, running: ```bash -$ rails generate migration AddDetailsToProducts 'price:decimal{5,2}' supplier:references{polymorphic} +$ bin/rails generate migration AddDetailsToProducts 'price:decimal{5,2}' supplier:references{polymorphic} ``` will produce a migration that looks like this @@ -653,7 +653,7 @@ is the numerical prefix on the migration's filename. For example, to migrate to version 20080906120000 run: ```bash -$ rake db:migrate VERSION=20080906120000 +$ bin/rake db:migrate VERSION=20080906120000 ``` If version 20080906120000 is greater than the current version (i.e., it is @@ -670,7 +670,7 @@ mistake in it and wish to correct it. Rather than tracking down the version number associated with the previous migration you can run: ```bash -$ rake db:rollback +$ bin/rake db:rollback ``` This will rollback the latest migration, either by reverting the `change` @@ -678,7 +678,7 @@ method or by running the `down` method. If you need to undo several migrations you can provide a `STEP` parameter: ```bash -$ rake db:rollback STEP=3 +$ bin/rake db:rollback STEP=3 ``` will revert the last 3 migrations. @@ -688,7 +688,7 @@ back up again. As with the `db:rollback` task, you can use the `STEP` parameter if you need to go more than one version back, for example: ```bash -$ rake db:migrate:redo STEP=3 +$ bin/rake db:migrate:redo STEP=3 ``` Neither of these Rake tasks do anything you could not do with `db:migrate`. They @@ -718,7 +718,7 @@ the corresponding migration will have its `change`, `up` or `down` method invoked, for example: ```bash -$ rake db:migrate:up VERSION=20080906120000 +$ bin/rake db:migrate:up VERSION=20080906120000 ``` will run the 20080906120000 migration by running the `change` method (or the @@ -734,7 +734,7 @@ To run migrations against another environment you can specify it using the migrations against the `test` environment you could run: ```bash -$ rake db:migrate RAILS_ENV=test +$ bin/rake db:migrate RAILS_ENV=test ``` ### Changing the Output of Running Migrations @@ -902,6 +902,11 @@ schema into a RDBMS other than the one used to create it. Because schema dumps are the authoritative source for your database schema, it is strongly recommended that you check them into source control. +`db/schema.rb` contains the current version number of the database. This +ensures conflicts are going to happen in the case of a merge where both +branches touched the schema. When that happens, solve conflicts manually, +keeping the highest version number of the two. + Active Record and Referential Integrity --------------------------------------- |