Sqlserver::Sequence

A Rails plugin for SQL Server sequences.

Installation

Add this line to your application's Gemfile:

gem 'sqlserver-sequence'

And then execute:

$ bundle

Or install it yourself as:

$ gem install sqlserver-sequence

Usage

Specify the attribute you'd like to sequence

class Supplier < ActiveRecord::Base
  sequence :number
end

Now when you create a record number will be assigned the next value for that sequence.

$ supplier = Supplier.create
$ supplier.number
> 10 # generated by sequence named 'number'

$ other_supplier = Supplier.create
$ other_supplier.number
> 11

You can also define multiple sequences

class Supplier < ActiveRecord::Base
  sequence :number
  sequence :purchase_order
end

Options

name

By default sqlserver-sequence will look for a row in sys.sequences with the same sequence_name as the attribute. You can use the name option if the sequence is named differently.

class Supplier < ActiveRecord::Base
  sequence :number, name: 'next_supplier_number'
end

$ supplier = Supplier.create
$ supplier.number 
> 10 # generated by sequence named 'next_supplier_number'

prefix

You can use the prefix option to prepend every sequence value with a string.

class Supplier < ActiveRecord::Base
  sequence :number, prefix: 'S-'
end

$ supplier = Supplier.create
$ supplier.number
> S-10

format

Pass a lambda to the format option if you need more control over the assigned sequence value, for example to assign a fixed length string.

class Supplier < ActiveRecord::Base
  sequence :number, prefix: 'S-',
                    format: lambda { |num| num.rjust(10, 0) }
end

$ supplier = Supplier.create
$ supplier.number
> S-0000000010

Configuration

Override any of these defaults in config/initializers/sqlserver_sequence.rb:

Sqlserver::Sequence.configure do |config|
  config.next_value_strategy = Sqlserver::Sequence::Strategies::NextValueFor
end

next_value_strategy

By default Sqlserver::Sequence will use a strategy that implements SQL Server's NEXT VALUE FOR function.

To change how sequences are generated you can also assign your own strategy:

# lib/size_strategy.rb
module SizeStrategy
  def next_sequence_value(sequence_name)
    self.class.size
  end
end

# config/initializers/sqlserver_sequence.rb
Sqlserver::Sequence.configure do |config|
  config.next_value_strategy = SizeStrategy
end

Development and Testing without SQL Server

If your test or development environment uses something other than SQL Server (e.g. SQLite) a Simple strategy is provided to avoid errors.

Sqlserver::Sequence.configure do |config|
  config.next_value_strategy = Sqlserver::Sequence::Strategies::Simple
end

Contributing

1. Fork it ( https://github.com/zacharywelch/sqlserver-sequence/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

See the Running Tests guide for details on how to run the test suite on SQL Server.