Module: CompositePrimaryKeys::ActiveRecord::FinderMethods

Defined in:
lib/composite_primary_keys/relation/finder_methods.rb

Instance Method Summary collapse

Instance Method Details

#construct_limited_ids_condition(relation) ⇒ Object 



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# File 'lib/composite_primary_keys/relation/finder_methods.rb', line 4

def construct_limited_ids_condition(relation)
  orders = relation.order_values
  # CPK
  # values = @klass.connection.distinct("#{@klass.connection.quote_table_name table_name}.#{primary_key}", orders)
  keys = @klass.primary_keys.map do |key|
    "#{@klass.connection.quote_table_name @klass.table_name}.#{key}"
  end
  values = @klass.connection.distinct(keys.join(', '), orders)

  relation = relation.dup

  ids_array = relation.select(values).collect {|row| row[primary_key]}
  # CPK
  # ids_array.empty? ? raise(ThrowResult) : table[primary_key].in(ids_array)

  # OR together each and expression (key=value and key=value) that matches an id set
  # since we only need to match 0 or more records
  or_expressions = ids_array.map do |id_set|
    # AND together "key=value" exprssios to match each id set
    and_expressions = [self.primary_keys, id_set].transpose.map do |key, id|
      table[key].eq(id)
    end
    Arel::Nodes::And.new(and_expressions)
  end

  first = or_expressions.shift
  Arel::Nodes::Grouping.new(or_expressions.inject(first) do |memo, expr|
      Arel::Nodes::Or.new(memo, expr)
  end)
end

#exists?(id = nil) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/composite_primary_keys/relation/finder_methods.rb', line 35

def exists?(id = nil)
  # ID can be:
  #   Array - ['department_id = ? and location_id = ?', 1, 1]
  #   Array -> [1,2]
  #   CompositeKeys -> [1,2]

  id = id.id if ::ActiveRecord::Base === id

  join_dependency = construct_join_dependency_for_association_find
  relation = construct_relation_for_association_find(join_dependency)
  relation = relation.except(:select).select("1").limit(1)

  # CPK
  #case id
  #when Array, Hash
  #  relation = relation.where(id)
  #else
  #  relation = relation.where(table[primary_key].eq(id)) if id
  #end

  case id
  when CompositePrimaryKeys::CompositeKeys
    relation = relation.where(cpk_id_predicate(table, primary_key, id))
  when Array
    pk_length = @klass.primary_keys.length

    if id.length == pk_length # E.g. id = ['France', 'Paris']
      return self.exists?(id.to_composite_keys)
    else # Assume that id contains where relation
      relation = relation.where(id)
    end
  when Hash
    relation = relation.where(id)
  end
  connection.select_value(relation.to_sql) ? true : false
end

#find_with_ids(*ids, &block) ⇒ Object 



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# File 'lib/composite_primary_keys/relation/finder_methods.rb', line 72

def find_with_ids(*ids, &block)
  return to_a.find { |*block_args| yield(*block_args) } if block_given?

  # Supports:
  #   find('1,2')             ->  ['1,2']
  #   find(1,2)               ->  [1,2]
  #   find([1,2])             -> [['1,2']]
  #   find([1,2], [3,4])      -> [[1,2],[3,4]]
  #
  # Does *not* support:
  #   find('1,2', '3,4')      ->  ['1,2','3,4']

  # Normalize incoming data.  Note the last arg can be nil.  Happens
  # when find is called with nil options which is then passed on
  # to find_with_ids.
  ids.compact!

  ids = [ids] unless ids.first.kind_of?(Array)

  results = ids.map do |cpk_ids|
    cpk_ids = if cpk_ids.length == 1
      cpk_ids.first.split(CompositePrimaryKeys::ID_SEP).to_composite_keys
    else
      cpk_ids.to_composite_keys
    end

    unless cpk_ids.length == @klass.primary_keys.length
      raise "#{cpk_ids.inspect}: Incorrect number of primary keys for #{@klass.name}: #{@klass.primary_keys.inspect}"
    end

    new_relation = clone
    [@klass.primary_keys, cpk_ids].transpose.map do |key, id|
      new_relation = new_relation.where(key => id)
    end

    records = new_relation.to_a

    if records.empty?
      conditions = new_relation.arel.where_sql
      raise(::ActiveRecord::RecordNotFound,
            "Couldn't find #{@klass.name} with ID=#{cpk_ids} #{conditions}")
    end
    records
  end.flatten

  ids.length == 1 ? results.first : results
end