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https://github.com/wmaciejak/sequel-combine
The Sequel extension adds the Sequel::Dataset#combine method, which returns object from database composed with childrens, parents or any object where exists any relationship. Now it is possible in one query!
https://github.com/wmaciejak/sequel-combine
database dataset orm postgres postgresql ruby sequel
Last synced: about 20 hours ago
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The Sequel extension adds the Sequel::Dataset#combine method, which returns object from database composed with childrens, parents or any object where exists any relationship. Now it is possible in one query!
- Host: GitHub
- URL: https://github.com/wmaciejak/sequel-combine
- Owner: wmaciejak
- License: mit
- Created: 2017-06-03T09:52:16.000Z (over 7 years ago)
- Default Branch: master
- Last Pushed: 2022-12-02T17:09:24.000Z (almost 2 years ago)
- Last Synced: 2024-04-10T01:41:57.320Z (7 months ago)
- Topics: database, dataset, orm, postgres, postgresql, ruby, sequel
- Language: Ruby
- Homepage:
- Size: 21.5 KB
- Stars: 30
- Watchers: 45
- Forks: 1
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE
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README
# SequelCombine
[](https://circleci.com/gh/wmaciejak/sequel-combine/tree/master) [](https://badge.fury.io/rb/sequel-combine) [](https://codeclimate.com/github/wmaciejak/sequel-combine)
This extension adds the `Sequel::Dataset#combine` method, which returns object from database composed with childrens, parents or any object where exists any relationship. Now it is possible in one query!
## Installation
Add this line to your application's Gemfile:
gem 'sequel-combine'
And then execute:
$ bundle
Or install it yourself as:
$ gem install sequel-combine
The plugin needs to be initialized by the Sequel extension interface. The simplest way to configure plugin globally is adding this line to the initializer:
```ruby
Sequel.extension :combine
```
or
```ruby
Sequel::Database.extension :combine
```
But anyway I recommend reading more about [Sequel extensions system](https://github.com/jeremyevans/sequel/blob/master/doc/extensions.rdoc#sequel-extensions).
## Usage
Remember!
**Combined dataset** it's still a dataset so methods can be chained!
Combining works only with **Postgres** adapter
```ruby
dataset_first
.combine(many: { attribute: [dataset_second, p_key_dataset_second: :f_key_dataset_first] })
.to_a
```
* `dataset_first`, `dataset_second` -> datasets which needs to be combined
* `many` -> method used in combining. If relation is one-to-one recommended method is `one`(which return object or nil), in any other case I recommend to using method `many`(which return array of objects or empty array).
* `attribute` -> attribute which will be an result of combine
* `p_key_dataset_second: :f_key_dataset_first` -> relationship between tables
## Usage examples
### Combining many
```ruby
DB[:groups].columns
#=> [:id, :name]
DB[:users].columns
#=> [:id, :username, :email, :group_id]
DB[:groups].combine(many: { users: [DB[:users], id: :group_id] }).to_a
#=> [{:id=>1,
# :name=>"Football",
# :users=>
# [{
# :id=> 1,
# :username=> "leonardo",
# :email=> "[email protected]",
# :group_id=> 1,
# },
# {
# :id=> 2,
# :username=> "leonardo2",
# :email=> "[email protected]",
# :group_id=> 1,
# },
# ]
# }]
```
### Combining one
```ruby
DB[:groups].columns
#=> [:id, :name]
DB[:users].columns
#=> [:id, :username, :email, :group_id]
DB[:users].combine(one: { group: [DB[:groups], group_id: :id] }).to_a
#=> [
# {
# :id=> 1,
# :username=> "leonardo",
# :email=> "[email protected]",
# :group=> { :id=> 1, :name=> "Football" },
# },
# {
# :id=> 2,
# :username=> "leonardo2",
# :email=> "[email protected]"
# :group=> { :id=> 1, :name=> "Football" },
# }
# ]
```
### Combining one and many
Also combining can be mixed and multiplied:
```ruby
DB[:users].combine(
one: {
group: [DB[:groups], group_id: :id],
company: [DB[:companies], company_id: :id],
},
many: {
tasks: [DB[:tasks], id: :user_id],
roles: [DB[:roles], id: :user_id],
},
).to_a
```
### Combining inside combine
It can go deeper and deeper...
```ruby
DB[:projects].combine(
many: {
users: [
DB[:users].combine(one: { city: [DB[:cities], city_id: :id] }),
id: :project_id,
]
}
).to_a
```
### Self-combining and combining not by foreign_key
```ruby
DB[:geolocations].combine(one: { parent: [DB[:geolocations], path: :parent_path] }).to_a
```
### Combining more complex datasets
Datasets used in combine might be of course chained with other `Sequel::Dataset` methods.
```ruby
DB[:groups]
.where(id: 1)
.select(:id, :name)
.order(:name)
.combine(
many: {
users: [
DB[:users]
.join(:groups)
.select(:id, :username, :group_id, Sequel.qualify("groups", "name")),
id: :group_id
]
}
).to_a
```
## Benchmark
Tested on 2000 mocked records with children's or parents:
4 level of combine - 2,39 sec.
3 level - 1,12 sec.
2 level - 0,55 sec.
1 level - 0,22 sec.
self-combining (the situation from geolocation, tested on real geolocations database, around 23000 records) - 4 sec
## Use cases
* API directly in Postgresql
* Exporting tree of objects
* **deep clone** in Postgresql - very extreme case, but it's probably the most performance effective way of doing this operation
* more, more, more...
## Contributing
1. Fork it
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 new Pull Request