DatabaseValidations
ActiveRecord provides validations on app level but it won’t guarantee the consistent. In some cases, like validates_uniqueness_of it executes additional SQL query to the database and that is not very efficient.
The main goal of the gem is to provide compatibility between database constraints and ActiveRecord validations with better performance and consistency.
Installation
Add this line to your application’s Gemfile:
“by gem ‘database_validations’
“
And then execute:
$ bundleOr install it yourself as:
$ gem install database_validationsvalidates_db_uniqueness_of
Supported databases: postgresql, mysql and sqlite.
Pros and Cons
Advantages: - Provides true uniqueness on the database level because it handles race conditions cases properly. - Check the existence of correct unique index at the boot time. - It’s faster. See Benchmark section for details.
Disadvantages: - Cannot handle multiple validations at once because database raises only one error for all indexes per query. “by class User < ActiveRecord::Base validates_db_uniqueness_of :email validates_db_uniqueness_of :name end
original = User.create(name: 'name', email: '[email protected]')
dupe = User.create(name: 'name', email: '[email protected]')
# => false
dupe.errors.messages
# => {:name=>["has already been taken"]}
```How it works?
We override save and save! methods where we rescue ActiveRecord::RecordNotUnique and add proper errors for compatibility.
For valid? we use implementation from validates_uniqueness_of where we query the database.
Usage
“by class User < ActiveRecord::Base validates_db_uniqueness_of :email end
original = User.create(email: ‘[email protected]’) dupe = User.create(email: ‘[email protected]’)
=> false
dupe.errors.messages
=>
User.create!(email: ‘[email protected]’)
=> ActiveRecord::RecordInvalid Validation failed: email has already been taken
“
Configuration options
We want to provide full compatibility with existing validates_uniqueness_of validator.
This list of supported options from validates_uniqueness_of validator:
scope: One or more columns by which to limit the scope of the uniqueness constraint.message: Specifies a custom error message (default is: “has already been taken”).
Keep in mind: Even when we don’t support case_sensitive, allow_nil and allow_blank options now, the following:
“by validates_db_uniqueness_of :email
“
Is the same by default as following
“by validates_uniqueness_of :email, allow_nil: true, allow_blank: false, case_sensitive: true
“
The list of options to add support:
conditions: Specify the conditions to be included as a WHERE SQL fragment to limit the uniqueness constraint lookup (e.g. conditions: -> { where(status: 'active') }).case_sensitive: Looks for an exact match. Ignored by non-text columns (trueby default).allow_nil: If set totrue, skips this validation if the attribute isnil(default isfalse).allow_blank: If set totrue, skips this validation if the attribute is blank (default isfalse).if: Specifies a method, proc or string to call to determine if the validation should occur (e.g. if: :allow_validation, or if: Proc.new { |user| user.signup_step > 2 }). The method, proc or string should return or evaluate to atrueorfalsevalue.unless: Specifies a method, proc or string to call to determine if the validation should not occur (e.g. unless: :skip_validation, orMaruku could not parse this XML/HTML: <tt>unless: Proc.new { |user| user.signup_step
Benchmark (code)
| Case | Validator | SQLite | PostgreSQL | MySQL |
|---|---|---|---|---|
| Save duplicate item only | validates_db_uniqueness_of | 1.404k (±14.7%) i/s - 6.912k in 5.043409s | 508.889 (± 2.8%) i/s - 2.550k in 5.015044s | 649.356 (±11.5%) i/s - 3.283k in 5.153444s |
| validates_uniqueness_of | 1.505k (±14.6%) i/s - 7.448k in 5.075696s | 637.017 (±14.1%) i/s - 3.128k in 5.043434s | 473.561 (± 9.7%) i/s - 2.352k in 5.021151s | |
| Save unique item only | validates_db_uniqueness_of | 3.241k (±18.3%) i/s - 15.375k in 5.014244s | 1.345k (± 5.5%) i/s - 6.834k in 5.096706s | 1.439k (±12.9%) i/s - 7.100k in 5.033603s |
| validates_uniqueness_of | 2.002k (±10.9%) i/s - 9.900k in 5.018449s | 667.100 (± 4.8%) i/s - 3.350k in 5.034451s | 606.334 (± 4.9%) i/s - 3.068k in 5.072587s | |
| Each hundredth item is duplicate | validates_db_uniqueness_of | 3.534k (± 5.6%) i/s - 17.748k in 5.039277s | 1.351k (± 6.5%) i/s - 6.750k in 5.017280s | 1.436k (±11.6%) i/s - 7.154k in 5.062644s |
| validates_uniqueness_of | 2.121k (± 6.8%) i/s - 10.653k in 5.049739s | 658.199 (± 6.1%) i/s - 3.350k in 5.110176s | 596.024 (± 6.7%) i/s - 2.989k in 5.041497s |
Development
You need to have installed and running postgresql and mysql. And for each adapter manually create a database called database_validations_test.
After checking out the repo, run bin/setup to install dependencies.
Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.
Contributing
Bug reports and pull requests are welcome on GitHub. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.
License
The gem is available as open source under the terms of the MIT License.
Code of Conduct
Everyone interacting in the DatabaseValidations project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.