Module: VersionedRecord::CompositePredicates

Defined in:
lib/versioned_record/composite_predicates.rb

Instance Method Summary collapse

Instance Method Details

#cpk_join_predicate(association_table, association_key, table, key) ⇒ Object

Lets say location belongs to a company and company is versioned

class Company < ActiveRecord::Base
  include VersionedRecord
  has_many :locations
end

class Location < ActiveRecord::Base
  belongs_to :company
end

When we want to load the company from the location we do:

location.company

This will do:

Company.where(id: location.company.id, is_current_version: true)

Parameters:

  • association_table (Arel::Table) —

    the associated_table (in the example, company)

  • association_key (Array, String) —

    the value of the pkey of associated_table (in the example, company)

  • table (Arel::Table) —

    (in the example, location)

  • key (Array, String) —

    reference to the association



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# File 'lib/versioned_record/composite_predicates.rb', line 28

def cpk_join_predicate(association_table, association_key, table, key)
  fields             = Array(key).map { |key| table[key] }
  association_fields = Array(association_key).map { |key| association_table[key] }

  if fields.size == 1
    eq_predicates = [ association_fields[0].eq(fields[0]) ]
    case association.reflection.macro
      when :belongs_to
        # We don't handle Polymorphic associations at this stage
        if !association.options[:polymorphic]
          if association.reflection.klass.versioned?
            eq_predicates << association_table[:is_current_version].eq(true)
          end
        end
      when :has_and_belongs_to_many
        if association.reflection.klass.versioned?
          if association.reflection.klass.table_name == association_table.name
            eq_predicates << association_table[:is_current_version].eq(true)
          end
        end
      when :has_many, :has_one
        if association.reflection.klass.versioned?
          if association.reflection.klass.table_name == association_table.name
            eq_predicates << association_table[:is_current_version].eq(true)
          end
        end
    end
    cpk_and_predicate(eq_predicates)
  else
    super
  end
end