Module: ROM::Plugins::Relation::SQL::AutoRestrictions

Extended by:
Notifications::Listener
Defined in:
lib/rom/plugins/relation/sql/auto_restrictions.rb

Overview

Generates methods for restricting relations by their indexed attributes

Examples:

rom = ROM.container(:sql, 'sqlite::memory') do |config|
  config.create_table(:users) do
    primary_key :id
    column :email, String, null: false, unique: true
  end

  config.plugin(:sql, relations: :auto_restrictions)

  config.relation(:users) do
    schema(infer: true)
  end
end

# now `by_email` is available automatically
rom.relations[:users].by_email('[email protected]')

Class Method Summary collapse

Class Method Details

.restriction_methods(schema) ⇒ Object

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future. 



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# File 'lib/rom/plugins/relation/sql/auto_restrictions.rb', line 42

def self.restriction_methods(schema)
  mod = Module.new

  methods = schema.indexes.each_with_object([]) do |index, generated|
    next if index.partial?

    attributes = index.to_a
    meth_name = :"by_#{ attributes.map(&:name).join('_and_') }"

    next if generated.include?(meth_name)

    mod.module_eval do
      if attributes.size == 1
        attribute = attributes[0]

        define_method(meth_name) do |value|
          where(attribute.is(value))
        end
      else
        indexed_attributes = attributes.map.with_index.to_a

        define_method(meth_name) do |*values|
          where(indexed_attributes.map { |attr, idx| attr.is(values[idx]) }.reduce(:&))
        end
      end
    end

    generated << meth_name
  end

  [methods, mod]
end