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Diffstat (limited to 'guides/source/active_record_basics.md')
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1 files changed, 17 insertions, 6 deletions
diff --git a/guides/source/active_record_basics.md b/guides/source/active_record_basics.md index d9e9466a33..9be9c6c7b7 100644 --- a/guides/source/active_record_basics.md +++ b/guides/source/active_record_basics.md @@ -20,7 +20,7 @@ After reading this guide, you will know: What is Active Record? ---------------------- -Active Record is the M in [MVC](http://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller) - the +Active Record is the M in [MVC](https://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 @@ -38,7 +38,7 @@ 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](https://en.wikipedia.org/wiki/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 @@ -104,7 +104,7 @@ depending on the purpose of these columns. your models. * **Primary keys** - By default, Active Record will use an integer column named `id` as the table's primary key. When using [Active Record - Migrations](migrations.html) to create your tables, this column will be + Migrations](active_record_migrations.html) to create your tables, this column will be automatically created. There are also some optional column names that will add additional features @@ -304,6 +304,17 @@ user = User.find_by(name: 'David') user.destroy ``` +If you'd like to delete several records in bulk, you may use `destroy_all` +method: + +```ruby +# find and delete all users named David +User.where(name: 'David').destroy_all + +# delete all users +User.destroy_all +``` + Validations ----------- @@ -314,8 +325,8 @@ already in the database, follows a specific format and many more. Validation is a very important issue to consider when persisting to the database, so the methods `save` and `update` take it into account when -running: they return `false` when validation fails and they didn't actually -perform any operation on the database. All of these have a bang counterpart (that +running: they return `false` when validation fails and they don't actually +perform any operations on the database. All of these have a bang counterpart (that is, `save!` and `update!`), which are stricter in that they raise the exception `ActiveRecord::RecordInvalid` if validation fails. A quick example to illustrate: @@ -374,4 +385,4 @@ and to roll it back, `rails db:rollback`. Note that the above code is database-agnostic: it will run in MySQL, PostgreSQL, Oracle and others. You can learn more about migrations in the -[Active Record Migrations guide](migrations.html). +[Active Record Migrations guide](active_record_migrations.html). |