Class: Sequel::SeekPagination::OrderedColumnSet

Inherits:
Object
  • Object
show all
Defined in:
lib/sequel/extensions/seek_pagination.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(order_values, include_exact_match:, not_null:) ⇒ OrderedColumnSet

Returns a new instance of OrderedColumnSet.



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# File 'lib/sequel/extensions/seek_pagination.rb', line 67

def initialize(order_values, include_exact_match:, not_null:)
  @not_null = not_null
  @include_exact_match = include_exact_match
  @orders = order_values.map { |order, value| OrderedColumn.new(self, order, value) }
end

Instance Attribute Details

#include_exact_match ⇒ Object (readonly)

Returns the value of attribute include_exact_match.



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# File 'lib/sequel/extensions/seek_pagination.rb', line 65

def include_exact_match
  @include_exact_match
end

#not_null ⇒ Object (readonly)

Returns the value of attribute not_null.



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# File 'lib/sequel/extensions/seek_pagination.rb', line 65

def not_null
  @not_null
end

#orders ⇒ Object (readonly)

Returns the value of attribute orders.



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# File 'lib/sequel/extensions/seek_pagination.rb', line 65

def orders
  @orders
end

Instance Method Details

#apply(dataset) ⇒ Object 



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# File 'lib/sequel/extensions/seek_pagination.rb', line 73

def apply(dataset)
  length = orders.length

  conditions =
    # Handle the common case where we can do a simpler (and faster)
    # WHERE (non_nullable_1, non_nullable_2) > (1, 2) clause.
    if length > 1 && orders.all?(&:not_null) && has_uniform_order_direction?
      Sequel.virtual_row do |o|
        o.__send__(
          orders.first.inequality_method(include_exact_match),
          orders.map(&:name),
          orders.map(&:value)
        )
      end
    else
      Sequel.&(
        *length.times.map { |i|
          allow_equal = include_exact_match || i != length - 1
          conditions = orders[0..i]

          if i.zero?
            conditions[0].ineq(eq: allow_equal)
          else
            c = conditions[-2]

            list = if filter = conditions[-1].ineq(eq: allow_equal)
                     [Sequel.&(c.eq_filter, filter)]
                   else
                     [c.eq_filter]
                   end

            list += conditions[0..-2].map { |c| c.ineq(eq: false) }

            Sequel.|(*list.compact)
          end
        }.compact
      )
    end

  dataset.where(conditions)
end