https://github.com/mcasimir/active_record_schema
ActiveRecord extension allowing to write schema in models and to generate migrations from models
https://github.com/mcasimir/active_record_schema
Last synced: about 2 months ago
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ActiveRecord extension allowing to write schema in models and to generate migrations from models
- Host: GitHub
- URL: https://github.com/mcasimir/active_record_schema
- Owner: mcasimir
- License: mit
- Created: 2012-05-05T22:04:46.000Z (about 13 years ago)
- Default Branch: master
- Last Pushed: 2023-01-09T22:14:14.000Z (over 2 years ago)
- Last Synced: 2025-03-26T08:37:09.900Z (2 months ago)
- Language: Ruby
- Size: 85.9 KB
- Stars: 4
- Watchers: 3
- Forks: 1
- Open Issues: 9
-
Metadata Files:
- Readme: README.md
- License: LICENSE.txt
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README
# ActiveRecordSchema
**ActiveRecordSchema** is an `ActiveRecord` extension that allows you to define fields for a model within the model itself and to generate migrations directly from models.
Unlike other libraries ActiveRecordSchema is not an alternative to Rails migrations, but rather a tool to simplify their use.
_ex._
```
rails g model Post title:string body:text --timestamps
```
``` rb
class Post < ActiveRecord::Base
field :title, :string
field :body, :text
attr_accessible :date, :name
timestamps
end
```
```
rails g migration:from post
create db/migrate/20120801104035_create_posts.rb
```
## Features
* Defining columns and indexes directly in model
* Generation of migration from the model taking into account the current state of the database
* Automatically add code to migrate associations:
* Foreign key for `belongs_to`
* Join table for `has_and_belongs_to_many`
* Automatic indexing of foreign keys for both `belongs_to` and `has_and_belongs_to_many` (configurable)
## Installation
Put this in your Gemfile
gem 'active_record_schema'
and update your bundle
bundle install
**NOTE:** ActiveRecordSchema depends on `rails ~> 3.0` and not only `ActiveRecord`
## Configuration
In order to correctly solve the required fields for the inheritance ActiveRecordSchema requires that all classes of models are loaded in memory when generating migration. This is done by pre-loading models in the generator. To figure out which file to load ARS refers to the global configuration property in `ActiveRecordSchema.config.autoload_paths` that is set by default to:
``` rb
[
Rails.root.join('app', 'models', '*.rb'),
Rails.root.join('app', 'models', '**', '*.rb')
]
```
You can change this by creating an initializer and setting or appending new paths to `ActiveRecordSchema.config.autoload_paths`
``` rb
# active_record_schema_initializer.rb
ActiveRecordSchema.config.autoload_paths << Rails.root.join('lib', 'models', '*.rb')
```
## Usage
Create a model and use the class method `#field` to define columns
``` rb
class Post < ActiveRecord::Base
field :title
field :body, :as => :text
belongs_to :author, :class_name => "User"
end
```
Now run `rails g migration` with `--from` option
rails g migration init_posts_schema --from Post
or just
rails g migration:from post
and the following migration will be generated
``` rb
class InitPostsSchema < ActiveRecord::Migration
def change
create_table :posts
add_column :posts, :title, :string
add_column :posts, :body, :text
add_column :author_id, :integer
index :author_id
end
end
```
**NOTE:** `create_table :posts` is added only if `posts` table does not exist yet
Generating a migration for new columns is the same, lets add a new field to `Post` (eg. `pubdate`):
``` rb
class Post < ActiveRecord::Base
field :title
field :body, :as => :text
belongs_to :author, :class_name => "User"
field :pubdate, :as => :datetime
end
```
Now run
rails g migration add_pubdate_to_posts --from Post
or just
rails g migration:from post --add pubdate
that will generate:
``` rb
class AddPubdateToPosts < ActiveRecord::Migration
def change
add_column :posts, :pubdate, :datetime
end
end
```
**NOTE:** No migration will be generated in case all changes are up-to-date
## Has and Belongs To Many (HBTM) associations
Lets try to add a HBTM association to our `Post` model
_ex._
``` rb
# post.rb
class Post < ActiveRecord::Base
field :title
field :body, :as => :text
belongs_to :author, :class_name => "User"
field :pubdate, :as => :datetime
has_and_belongs_to_many :voters, :class_name => "User"
end
```
Now running
rails g migration add_voters_to_posts --from Post
will generate:
``` rb
class AddVotersToPosts < ActiveRecord::Migration
def change
create_table :posts_users, :id => false do |t|
t.integer "post_id"
t.integer "user_id"
end
add_index :posts_users, "post_id"
add_index :posts_users, "user_id"
end
end
```
## Single Table Inheritance (STI)
Call `#inheritable` inside the base class of your hierarchy to add the inheritance column required by Single Table Inheritance.
_ex._
``` rb
# content.rb
class Content < ActiveRecord::Base
inheritable
field :title
has_and_belongs_to_many :voters, :class_name => "User"
belongs_to :author, :class_name => "User"
timestamps
end
# article.rb
class Article < Content
field :body, :as => :text
end
# video.rb
class Video < Content
field :url
end
```
Running
rails g migration init_contents --from Content
same as
rails g migration init_contents --from Article
same as
rails g migration init_contents --from Video
will generate the following migration
``` rb
class InitContents < ActiveRecord::Migration
def change
add_column :contents, :type, :string
add_column :contents, :title, :string
add_column :contents, :author_id, :string
add_column :contents, :body, :text
add_column :contents, :url, :string
add_index :contents, :author_id
create_table :contents_users, :id => false do |t|
t.integer "content_id"
t.integer "user_id"
end
add_index :contents_users, "content_id"
add_index :contents_users, "user_id"
end
end
```
## Mixins
Probably one of the most significant advantage given by ActiveRecordSchema is to allow the definition of fields in modules and reuse them through mixins
_ex._
``` rb
module Profile
extend ActiveSupport::Concern
included do
field :name
field :age, :as => :integer
end
end
class User < ActiveRecord::Base
include Profile
end
class Player < ActiveRecord::Base
include Profile
end
```
## DSL (Domain Specific Language) reference
* ### `field(name, *args)`
Adds a new column with name `name` to the schema. The type of column can be passed either as second argument or as option, if not specified is intended to be `:string`
#### options
* **:as** _or_ **:type** : Specify the type of the column. The value can be a `String`, a `Symbol` or a `Class`, default to `:string`
* **:index** : Specify wether or not the field should be indexed, default to `false`
#### examples
``` rb
field :name
field :name, :string
field :name, "string"
field :name, String
field :name, :as => :string
field :name, :as => "string"
field :name, :as => String
field :name, :type => :string
field :name, :type => "string"
field :name, :type => String
field :age, :as => :integer, :index => true
```
* ### `belongs_to(name, options = {})`
Adds a new foreign key column for the association to the schema and then delegates to `ActiveRecord::Base.belongs_to`. If the association is polymorphic a column for foreign type is also generated.
#### options
* **:index** : Specify wether or not the foreing key column should be indexed, default to `true`. If the association is polymorphic creates an index on both foreign key and foreing type
* ### `has_and_belongs_to_many(name, options = {}, &extension)`
Adds a new join table for the association to the schema and then delegates to `ActiveRecord::Base.has_and_belongs_to_many`
* ### `index(column_name, options = {})`
Adds a new index for `column_name` column to the schema
* ### `add_index(column_name, options = {})`
alias for `index`
* ### `timestamps`
Same as
``` rb
field :created_at, :datetime
field :updated_at, :datetime
```
* ### `inheritable`
Same as
``` rb
field :"#{inheritance_column}"
```
## Generators
### `rails g migration:from`
Generates one or more migration from models
*eg.*
```
rails g migration:from link setting user menu photo photogallery
create db/migrate/20120801104031_create_links.rb
create db/migrate/20120801104032_create_settings.rb
create db/migrate/20120801104033_create_users.rb
create db/migrate/20120801104034_create_menus.rb
create db/migrate/20120801104035_create_photos.rb
create db/migrate/20120801104036_create_photogalleries.rb
```
You can also generate a migration to add columns setting its name in a handy way *eg.*
``` sh
rails g migration:from post --add title description
create db/migrate/20120801104036_add_title_and_description_to_posts.rb
```
```
Usage:
rails generate migration:from [model model] [options]
Options:
[--add=attrname attrname] # Indicates when to generate add
```
## Why do not also generate irreversible changes (change/remove columns or indexes)?
ActiveRecordSchema does not take into account the removal of columns and indexes or changes in the types of columns. The reason for this is that these changes are not reversible, so it's a better idea to introduce them by hand rather than let them be generated automatically. Anyway the need to resort to harsh measures such as irreversible changes is limited to non-routine situations.
## Contributing to active_record_schema
* Check out the latest master to make sure the feature hasn't been implemented or the bug hasn't been fixed yet.
* Check out the issue tracker to make sure someone already hasn't requested it and/or contributed it.
* Fork the project.
* Start a feature/bugfix branch.
* Commit and push until you are happy with your contribution.
* Make sure to add tests for it. This is important so I don't break it in a future version unintentionally.
* Please try not to mess with the Rakefile, version, or history. If you want to have your own version, or is otherwise necessary, that is fine, but please isolate to its own commit so I can cherry-pick around it.
---
Copyright (c) 2012 mcasimir
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
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permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.