Module: Sequel::Extensions::CountComparisons

Defined in:
lib/sequel/extensions/count_comparisons.rb

Instance Method Summary collapse

Instance Method Details

#count_equals?(number_of_rows) ⇒ Boolean

Returns true if exactly number_of_rows records exist in the dataset, false otherwise

Equivalent to an “equal to” (==) comparison

Parameters:

  • number_of_rows (Integer) —

    The number to compare against

Returns:

  • (Boolean) —

    Whether the dataset contains exactly number_of_rows

Raises:

  • (ArgumentError) —

    If ‘number_of_rows` is not an integer



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# File 'lib/sequel/extensions/count_comparisons.rb', line 70

def count_equals?(number_of_rows)
  unless number_of_rows.is_a?(Integer)
    raise ArgumentError,
          "`number_of_rows` must be an Integer, got #{number_of_rows.inspect}"
  end

  if number_of_rows.negative?
    false
  elsif number_of_rows.zero?
    empty?
  else
    ds = @opts[:sql] ? from_self : self
    ds = ds.unordered.select(LITERAL_1)
    @db.get(
      ds.offset(number_of_rows - 1).exists &
      ~ds.offset(number_of_rows).exists
    )
  end
end

#count_greater_than?(number_of_rows) ⇒ Boolean

Returns true if more than number_of_rows records exist in the dataset, false otherwise

Equivalent to a “greater than” (>) comparison

Parameters:

  • number_of_rows (Integer) —

    The number to compare against

Returns:

  • (Boolean) —

    Whether the dataset contains more rows than number_of_rows

Raises:

  • (ArgumentError) —

    If ‘number_of_rows` is not an integer



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# File 'lib/sequel/extensions/count_comparisons.rb', line 31

def count_greater_than?(number_of_rows)
  unless number_of_rows.is_a?(Integer)
    raise ArgumentError,
          "`number_of_rows` must be an Integer, got #{number_of_rows.inspect}"
  end

  if number_of_rows.negative?
    true
  elsif number_of_rows.zero?
    !empty?
  else
    ds = @opts[:sql] ? from_self : self
    !ds.offset(number_of_rows).empty?
  end
end

#count_less_than?(number_of_rows) ⇒ Boolean

Returns true if fewer than number_of_rows records exist in the dataset, false otherwise

Equivalent to a “less than” (<) comparison

Parameters:

  • number_of_rows (Integer) —

    The number to compare against

Returns:

  • (Boolean) —

    Whether the dataset contains fewer rows than number_of_rows

Raises:

  • (ArgumentError) —

    If ‘number_of_rows` is not an integer



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# File 'lib/sequel/extensions/count_comparisons.rb', line 54

def count_less_than?(number_of_rows)
  unless number_of_rows.is_a?(Integer)
    raise ArgumentError,
          "`number_of_rows` must be an Integer, got #{number_of_rows.inspect}"
  end

  !count_greater_than?(number_of_rows - 1)
end