Contents

module CompositePrimaryKeys
  module Predicates
    def cpk_and_predicate(predicates)
      if predicates.length == 1
        predicates.first
      else
        Arel::Nodes::And.new(predicates)
      end
    end
    
    def cpk_or_predicate(predicates)
      # Can't do or here, arel does the wrong thing and makes a really
      # deeply nested stack that blows up
      predicates.map do |predicate|
        predicate.to_sql
      end.join(" OR ")
    end

    def cpk_id_predicate(table, keys, values)
      eq_predicates = keys.zip(values).map do |key, value|
        table[key].eq(value)
      end
      cpk_and_predicate(eq_predicates)
    end

    def cpk_join_predicate(table1, key1, table2, key2)
      key1_fields = Array(key1).map {|key| table1[key]}
      key2_fields = Array(key2).map {|key| table2[key]}

      eq_predicates = key1_fields.zip(key2_fields).map do |key_field1, key_field2|
        key_field1.eq(key_field2)
      end
      cpk_and_predicate(eq_predicates)
    end

    def cpk_in_predicate(table, primary_keys, ids)
      and_predicates = ids.map do |id_set|
        eq_predicates = Array(primary_keys).zip(Array(id_set)).map do |primary_key, value|
          table[primary_key].eq(value)
        end
        cpk_and_predicate(eq_predicates)
      end

      cpk_or_predicate(and_predicates)
    end
  end
end

ActiveRecord::Associations::AssociationScope.send(:include, CompositePrimaryKeys::Predicates)
ActiveRecord::Associations::HasAndBelongsToManyAssociation.send(:include, CompositePrimaryKeys::Predicates)
ActiveRecord::Associations::JoinDependency::JoinAssociation.send(:include, CompositePrimaryKeys::Predicates)
ActiveRecord::Associations::Preloader::Association.send(:include, CompositePrimaryKeys::Predicates)
ActiveRecord::Relation.send(:include, CompositePrimaryKeys::Predicates)

Version data entries

1 entries across 1 versions & 1 rubygems

Version	Path
composite_primary_keys-4.0.0.beta6	lib/composite_primary_keys/composite_predicates.rb