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https://github.com/64kramsystem/json_on_rails
MySQL JSON support for Rails 4
https://github.com/64kramsystem/json_on_rails
json json-columns mysql rails rails4 ruby
Last synced: 18 days ago
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MySQL JSON support for Rails 4
- Host: GitHub
- URL: https://github.com/64kramsystem/json_on_rails
- Owner: 64kramsystem
- License: gpl-3.0
- Created: 2018-02-10T22:13:42.000Z (almost 7 years ago)
- Default Branch: master
- Last Pushed: 2019-09-19T17:44:32.000Z (about 5 years ago)
- Last Synced: 2024-10-18T18:58:46.114Z (about 1 month ago)
- Topics: json, json-columns, mysql, rails, rails4, ruby
- Language: Ruby
- Size: 47.9 KB
- Stars: 15
- Watchers: 3
- Forks: 2
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
[](https://travis-ci.org/saveriomiroddi/json_on_rails)
[](https://coveralls.io/github/saveriomiroddi/json_on_rails?branch=master)
# JSON on Rails
This gem adds native support for MySQL [5.7+] JSON data type to Rails 4.2.
## Introduction
Rails 5 introduced native support for the [MySQL] JSON data type; however, due to the Rails feature policy, version 4 won't receive this functionality.
This gem adds a Rails JSON data type, allowing the user to work with JSON attributes transparently, as a Array/Hash/etc.
The inner working is simple, and uses the standard Rails (internal) APIs; this is explained in a [blog post of mine](https://saveriomiroddi.github.io/Support-MySQL-native-JSON-data-type-in-Rails-4).
## Installation
Add the gem to the Gemfile of your rails project:
```ruby
gem "json_on_rails", "~> 0.2.0"
```
and update the environment:
```sh
$ bundle install
```
Change the `mysql` connection adapter to `mysql2_json`, in `config/database.yml`:
```yaml
default: &default
adapter: mysql2_json
```
that's all!
## Usage/example
Create a table:
```
class CreateUsers < ActiveRecord::Migration
def change
create_table "migration_models" do |t|
t.string "login", null: false, limit: 24
t.json "extras"
end
end
end
```
or add the column to an existing one:
```
class CreateUsers < ActiveRecord::Migration
def change
add_column "users", "extras", :json
end
end
```
define the model (rails will automatically pick up the data type):
```
class User < ActiveRecord::Base; end
```
then (ab)use the new attribute!:
```ruby
User.create!(login: "saverio", extras: {"uses" => ["mysql", "json"]})
# ...
User.last.extras.fetch("uses") # => ["mysql", "json"]
```
The schema can be dumped as usual; json columns will be transparently included:
```sh
$ rake db:schema:dump
$ cat db/schema.rb
ActiveRecord::Schema.define(version: 0) do
create_table "users", force: :cascade do |t|
t.json "extras"
end
end
```
## Caveats/further documentation
### MySQL SELECT DISTINCT JSON bug (**IMPORTANT!**)
MySQL versions up to at least 5.7.12 have a serious JSON bug.
In some cases, queries using DISTINCT on VARCHAR and JSON columns will not perform the deduplication, resulting in duplicate rows being returned, if there are any.
This has been fixed between 5.7.13 and 5.7.18 (I couldn't find the related enty in the release notes), therefore, MySQL 5.7 users are urged to upgrade to a recent version if they use JSON columns.
### Documentation
Users are encouraged to have a look at the test suite (especially [here](spec/json_on_rails/json_attributes_spec.rb) and [here](spec/json_on_rails/arel_methods_spec.rb)) for an exhaustive view of the functionality.
### JSON Symbols
Don't forget that JSON doesn't support symbols, therefore, they can be set, but are accessed/loaded as strings.
### MySQL decimal normalization
MySQL (up to 8.0.3, included) will normalize decimal numbers with zero fractional (e.g. `5.0`) to integers, therefore, changing the data type on save.
See [relevant bug](https://bugs.mysql.com/bug.php?id=88230).