build_fixture_sql

# File activerecord/lib/active_record/connection_adapters/abstract/database_statements.rb, line 558
        def build_fixture_sql(fixtures, table_name)
          columns = schema_cache.columns_hash(table_name).reject { |_, column| supports_virtual_columns? && column.virtual? }

          values_list = fixtures.map do |fixture|
            fixture = fixture.stringify_keys

            unknown_columns = fixture.keys - columns.keys
            if unknown_columns.any?
              raise Fixture::FixtureError, %(table "#{table_name}" has no columns named #{unknown_columns.map(&:inspect).join(', ')}.)
            end

            columns.map do |name, column|
              if fixture.key?(name)
                type = lookup_cast_type_from_column(column)
                with_yaml_fallback(type.serialize(fixture[name]))
              else
                default_insert_value(column)
              end
            end
          end

          table = Arel::Table.new(table_name)
          manager = Arel::InsertManager.new(table)

          if values_list.size == 1
            values = values_list.shift
            new_values = []
            columns.each_key.with_index { |column, i|
              unless values[i].equal?(DEFAULT_INSERT_VALUE)
                new_values << values[i]
                manager.columns << table[column]
              end
            }
            values_list << new_values
          else
            columns.each_key { |column| manager.columns << table[column] }
          end

          manager.values = manager.create_values_list(values_list)
          visitor.compile(manager.ast)
        end