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https://github.com/twilightcoders/active_record-mti
ActiveRecord support for PostgreSQL's native inherited tables (multi-table inheritance)
https://github.com/twilightcoders/active_record-mti
activerecord multi-table-inheritance postgresql
Last synced: 3 days ago
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ActiveRecord support for PostgreSQL's native inherited tables (multi-table inheritance)
- Host: GitHub
- URL: https://github.com/twilightcoders/active_record-mti
- Owner: TwilightCoders
- License: mit
- Created: 2016-09-10T03:15:05.000Z (over 8 years ago)
- Default Branch: develop
- Last Pushed: 2020-10-17T20:07:09.000Z (about 4 years ago)
- Last Synced: 2024-12-14T00:47:13.327Z (15 days ago)
- Topics: activerecord, multi-table-inheritance, postgresql
- Language: Ruby
- Homepage:
- Size: 186 KB
- Stars: 98
- Watchers: 2
- Forks: 8
- Open Issues: 7
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE.txt
Awesome Lists containing this project
README
[](https://rubygems.org/gems/active_record-mti)
[](https://travis-ci.org/TwilightCoders/active_record-mti)
[](https://codeclimate.com/github/TwilightCoders/active_record-mti/maintainability)
[](https://codeclimate.com/github/TwilightCoders/active_record-mti/coverage)
[](https://depfu.com/github/TwilightCoders/active_record-mti)
# ActiveRecord::MTI
ActiveRecord support for PostgreSQL's native inherited tables (multi-table inheritance)
**Supports**
- Ruby: `2.3`, `2.4`, `2.5`
- ActiveRecord: `4.2`, `5.0`, `5.1`
Confirmed production use in `4.2`
## Installation
Add this line to your application's Gemfile:
gem 'active_record-mti'
And then execute:
$ bundle
Or install it yourself as:
$ gem install active_record-mti
## Usage
```ruby
class Account < ::ActiveRecord::Base
# table_name is 'accounts'
# ...
end
class User < Account
# table_name is 'account/users'
# ...
end
class Developer < Account
# table_name is 'account/developers'
# ...
end
class Admin < User
self.table_name = 'admins'
# ...
end
class Hacker < Developer
# table_name is 'account/developer/hackers'
# ...
end
```
In most cases, you shouldn't have to do anything beyond installing the gem. `ActiveRecord::MTI` will do it's best to determine the nature of inheritance in your models. If your models map to their own tables, `ActiveRecord::MTI` will step in and make sure inheritance is treated appropriately. Otherwise it will gracefully acquiesce to `ActiveRecord`'s built-in `STI`. _(see Table Names section below)_.
### Queries
`ActiveRecord` queries work as usual with the following differences:
- The default query of "\*" is changed to include the OID of each row for subclass discrimination. The default select will be `SELECT "accounts"."tableoid" AS tableoid, "accounts".*` (for example)
### Table Names
Conventionally—to indicate the nature of inheritance—`ActiveRecord::MTI` expects the `table_name` of a child model to follow the `singular_parent_table_name/plural_child_table_name` pattern. As always, if you need to deviate from this, you can explicitly set the `table_name` as shown below, or configure `ActiveRecord::MTI` using the configure block.
Note, `ActiveRecord::MTI` will fall back on the unnested `table_name` if it's unable to find the nested form, and short of that, it will use the superclass's `table_name`.
### Configuration
`ActiveRecord::MTI` can be configured using a configure block.
```ruby
# config/initializers/active_record_mti.rb
ActiveRecord::MTI.configure do |config|
config.table_name_nesting = true
config.nesting_seperator = '/'
config.singular_parent = true
end
```
### Migrations
In your migrations define a table to inherit from another table:
```ruby
class CreateAccounts < ActiveRecord::Migration
def change
create_table :accounts do |t|
t.jsonb :settings
t.timestamps null: false
end
create_table :users, inherits: :accounts do |t|
t.string :firstname
t.string :lastname
end
create_table :developers, inherits: :users do |t|
t.string :url
t.string :api_key
end
end
end
```
### Schema
A schema will be created that reflects the inheritance chain so that `rake:db:schema:load` will work
```ruby
ActiveRecord::Schema.define(version: 20160910024954) do
create_table "accounts", force: :cascade do |t|
t.jsonb "settings"
t.datetime "created_at", null: false
t.datetime "updated_at", null: false
end
create_table "users", inherits: "accounts" do |t|
t.string "firstname"
t.string "lastname"
end
create_table "developers", inherits: "users" do |t|
t.string "url"
t.string "api_key"
end
end
```
## Contributing
1. Fork it ( https://github.com/TwilightCoders/active_record-mti/fork )
2. Create your feature branch (`git checkout -b my-new-feature`)
3. Commit your changes (`git commit -am 'Add some feature'`)
4. Push to the branch (`git push origin my-new-feature`)
5. Create a new Pull Request