Module: CompositePrimaryKeys::Predicates

Extended by:
Predicates
Included in:
Predicates
Defined in:
lib/composite_primary_keys/composite_predicates.rb

Instance Method Summary collapse

Instance Method Details

#cpk_and_predicate(predicates) ⇒ Object 



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# File 'lib/composite_primary_keys/composite_predicates.rb', line 7

def cpk_and_predicate(predicates)
  if predicates.length == 1
    predicates.first
  else
    Arel::Nodes::And.new(predicates)
  end
end

#cpk_id_predicate(table, keys, values) ⇒ Object 



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# File 'lib/composite_primary_keys/composite_predicates.rb', line 34

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

#cpk_in_predicate(table, primary_keys, ids) ⇒ Object 



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# File 'lib/composite_primary_keys/composite_predicates.rb', line 52

def cpk_in_predicate(table, primary_keys, ids)
  and_predicates = ids.map do |id|
    cpk_id_predicate(table, primary_keys, id)
  end
  cpk_or_predicate(and_predicates)
end

#cpk_join_predicate(table1, key1, table2, key2) ⇒ Object 



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# File 'lib/composite_primary_keys/composite_predicates.rb', line 41

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_field2 = Arel::Nodes::Quoted.new(key_field2) unless Arel::Attributes::Attribute === key_field2
    key_field1.eq(key_field2)
  end
  cpk_and_predicate(eq_predicates)
end

#cpk_or_predicate(predicates, group = true) ⇒ Object 



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# File 'lib/composite_primary_keys/composite_predicates.rb', line 15

def cpk_or_predicate(predicates, group = true)
  if predicates.length <= 1
    predicates.first
  else
    split_point = predicates.length / 2
    predicates_first_half = predicates[0...split_point]
    predicates_second_half = predicates[split_point..-1]

    or_predicate = ::Arel::Nodes::Or.new(cpk_or_predicate(predicates_first_half, false),
                                         cpk_or_predicate(predicates_second_half, false))

    if group
      ::Arel::Nodes::Grouping.new(or_predicate)
    else
      or_predicate
    end
  end
end