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Diffstat (limited to 'guides/source/active_record_basics.md')
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diff --git a/guides/source/active_record_basics.md b/guides/source/active_record_basics.md index eff93ce41d..dafbe17bbd 100644 --- a/guides/source/active_record_basics.md +++ b/guides/source/active_record_basics.md @@ -1,3 +1,5 @@ +**DO NOT READ THIS FILE ON GITHUB, GUIDES ARE PUBLISHED ON http://guides.rubyonrails.org.** + Active Record Basics ==================== @@ -18,7 +20,7 @@ After reading this guide, you will know: What is Active Record? ---------------------- -Active Record is the M in [MVC](getting_started.html#the-mvc-architecture) - the +Active Record is the M in [MVC](http://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller) - the model - which is the layer of the system responsible for representing business data and logic. Active Record facilitates the creation and use of business objects whose data requires persistent storage to a database. It is an @@ -31,12 +33,12 @@ Object Relational Mapping system. in his book _Patterns of Enterprise Application Architecture_. In Active Record, objects carry both persistent data and behavior which operates on that data. Active Record takes the opinion that ensuring -data access logic is part of the object will educate users of that +data access logic as part of the object will educate users of that object on how to write to and read from the database. ### Object Relational Mapping -Object-Relational Mapping, commonly referred to as its abbreviation ORM, is +Object Relational Mapping, commonly referred to as its abbreviation ORM, is a technique that connects the rich objects of an application to tables in a relational database management system. Using ORM, the properties and relationships of the objects in an application can be easily stored and @@ -60,7 +62,7 @@ Convention over Configuration in Active Record When writing applications using other programming languages or frameworks, it may be necessary to write a lot of configuration code. This is particularly true for ORM frameworks in general. However, if you follow the conventions adopted by -Rails, you'll need to write very little configuration (in some case no +Rails, you'll need to write very little configuration (in some cases no configuration at all) when creating Active Record models. The idea is that if you configure your applications in the very same way most of the time then this should be the default way. Thus, explicit configuration would be needed @@ -72,8 +74,8 @@ By default, Active Record uses some naming conventions to find out how the mapping between models and database tables should be created. Rails will pluralize your class names to find the respective database table. So, for a class `Book`, you should have a database table called **books**. The Rails -pluralization mechanisms are very powerful, being capable to pluralize (and -singularize) both regular and irregular words. When using class names composed +pluralization mechanisms are very powerful, being capable of pluralizing (and +singularizing) both regular and irregular words. When using class names composed of two or more words, the model class name should follow the Ruby conventions, using the CamelCase form, while the table name must contain the words separated by underscores. Examples: @@ -116,11 +118,11 @@ to Active Record instances: locking](http://api.rubyonrails.org/classes/ActiveRecord/Locking.html) to a model. * `type` - Specifies that the model uses [Single Table - Inheritance](http://api.rubyonrails.org/classes/ActiveRecord/Base.html#label-Single+table+inheritance). + Inheritance](http://api.rubyonrails.org/classes/ActiveRecord/Base.html#class-ActiveRecord::Base-label-Single+table+inheritance). * `(association_name)_type` - Stores the type for [polymorphic associations](association_basics.html#polymorphic-associations). * `(table_name)_count` - Used to cache the number of belonging objects on - associations. For example, a `comments_count` column in a `Articles` class that + associations. For example, a `comments_count` column in an `Article` class that has many instances of `Comment` will cache the number of existent comments for each article. @@ -140,7 +142,7 @@ end This will create a `Product` model, mapped to a `products` table at the database. By doing this you'll also have the ability to map the columns of each row in that table with the attributes of the instances of your model. Suppose -that the `products` table was created using an SQL sentence like: +that the `products` table was created using an SQL statement like: ```sql CREATE TABLE products ( @@ -171,18 +173,18 @@ name that should be used: ```ruby class Product < ActiveRecord::Base - self.table_name = "PRODUCT" + self.table_name = "my_products" end ``` If you do so, you will have to define manually the class name that is hosting -the fixtures (class_name.yml) using the `set_fixture_class` method in your test +the fixtures (my_products.yml) using the `set_fixture_class` method in your test definition: ```ruby -class FunnyJoke < ActiveSupport::TestCase - set_fixture_class funny_jokes: Joke - fixtures :funny_jokes +class ProductTest < ActiveSupport::TestCase + set_fixture_class my_products: Product + fixtures :my_products ... end ``` @@ -258,7 +260,7 @@ david = User.find_by(name: 'David') ```ruby # find all users named David who are Code Artists and sort by created_at in reverse chronological order -users = User.where(name: 'David', occupation: 'Code Artist').order('created_at DESC') +users = User.where(name: 'David', occupation: 'Code Artist').order(created_at: :desc) ``` You can learn more about querying an Active Record model in the [Active Record @@ -358,7 +360,7 @@ class CreatePublications < ActiveRecord::Migration t.string :publisher_type t.boolean :single_issue - t.timestamps + t.timestamps null: false end add_index :publications, :publication_type_id end |