Class: Arel::Order

Inherits:
Compound show all
Defined in:
lib/arel/algebra/relations/operations/order.rb,
lib/arel/engines/memory/relations/operations.rb

Instance Attribute Summary

Attributes inherited from Compound

#relation

Attributes included from Relation

#count

Instance Method Summary collapse

Methods inherited from Compound

#attributes, #build_query, #engine, #eql?, #hash, requires, #unoperated_rows

Methods included from Relation

#bind, #call, #christener, #compiler, #exclusion_predicate_sql, #externalizable?, #externalize, #inclusion_predicate_sql, #join?, #primary_key, #session, #to_sql

Methods included from Relation::DefaultOperations

#attributes, #groupings, #havings, #inserts, #joins, #locked, #projections, #skipped, #sources, #taken, #wheres

Methods included from Relation::AttributeAccessable

#[], #find_attribute_matching_attribute, #find_attribute_matching_name, #position_of

Methods included from Relation::Operable

#alias, #join, #lock, #outer_join

Methods included from Relation::Operable::Writable

#delete, #insert, #update

Methods included from Relation::Enumerable

#each, #first

Constructor Details

#initialize(relation, *orderings, &block) ⇒ Order

Returns a new instance of Order.



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# File 'lib/arel/algebra/relations/operations/order.rb', line 7

def initialize(relation, *orderings, &block)
  @relation = relation
  @orderings = (orderings + arguments_from_block(relation, &block)) \
    .collect { |o| o.bind(relation) }
end

Instance Method Details

#eval ⇒ Object 



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# File 'lib/arel/engines/memory/relations/operations.rb', line 9

def eval
  unoperated_rows.sort do |row1, row2|
    ordering = orders.detect { |o| o.eval(row1, row2) != 0 } || orders.last
    ordering.eval(row1, row2)
  end
end

#orders ⇒ Object

TESTME



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# File 'lib/arel/algebra/relations/operations/order.rb', line 14

def orders
  # QUESTION - do we still need relation.orders ?
  (orderings + relation.orders).collect { |o| o.bind(self) }.collect { |o| o.to_ordering }
end