Class: QueryHelper::SqlSort

Inherits:
Object
  • Object
show all
Defined in:
lib/query_helper/sql_sort.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(sort_string: "", sort_tiebreak: "", column_maps: [], column_sort_order: {}, keep_nulls_last: false) ⇒ SqlSort

Returns a new instance of SqlSort.



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# File 'lib/query_helper/sql_sort.rb', line 8

def initialize(sort_string: "", sort_tiebreak: "", column_maps: [], column_sort_order: {}, keep_nulls_last: false)
  @sort_string = sort_string
  @column_maps = column_maps
  @sort_tiebreak = sort_tiebreak
  @column_sort_order = column_sort_order
  @select_strings = []
  @keep_nulls_last = keep_nulls_last
end

Instance Attribute Details

#column_maps ⇒ Object

Returns the value of attribute column_maps.



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# File 'lib/query_helper/sql_sort.rb', line 6

def column_maps
  @column_maps
end

#column_sort_order ⇒ Object

Returns the value of attribute column_sort_order.



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# File 'lib/query_helper/sql_sort.rb', line 6

def column_sort_order
  @column_sort_order
end

#select_strings ⇒ Object

Returns the value of attribute select_strings.



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# File 'lib/query_helper/sql_sort.rb', line 6

def select_strings
  @select_strings
end

#sort_tiebreak ⇒ Object

Returns the value of attribute sort_tiebreak.



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# File 'lib/query_helper/sql_sort.rb', line 6

def sort_tiebreak
  @sort_tiebreak
end

Instance Method Details

#attributes_sql_expression(sort_attribute) ⇒ Object 



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# File 'lib/query_helper/sql_sort.rb', line 28

def attributes_sql_expression(sort_attribute)
  sql_strings = []
  if sort_attribute.present?
    sorts = sort_attribute.split(",")
    sorts.each_with_index do |sort, index|
      sort_alias = sort.split(":")[0]
      direction = sort.split(":")[1]
      modifier = sort.split(":")[2]
      begin
        sql_expression = @column_maps.find{ |m| m.alias_name.casecmp?(sort_alias) }.sql_expression
      rescue NoMethodError => e
        raise InvalidQueryError.new("Sorting not allowed on column '#{sort_alias}'")
      end

      if direction == "desc"
        case ActiveRecord::Base.connection.adapter_name
        when "SQLite" # SQLite is used in the test suite
          direction = @keep_nulls_last ? "desc nulls last" : "desc"
        else
          direction = "desc nulls last"
        end
      else
        direction = @keep_nulls_last ? "asc nulls last" : "asc"
      end

      case modifier
      when "lowercase"
        sql_expression = "lower(#{sql_expression})"
        # When select distincts are used, the order by clause must be included in the select clause
        @select_strings << sql_expression
      end

      sql_strings << "#{sql_expression} #{direction}"
    end
  end
  sql_strings << parse_custom_sort_string if @column_sort_order.present? && @column_sort_order[:sort_values].present?
  sql_strings
end

#parse_custom_sort_string ⇒ Object

This method is used for sorting enum based column



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# File 'lib/query_helper/sql_sort.rb', line 68

def parse_custom_sort_string
  sort_column = @column_sort_order[:column_name]
  sort_values = @column_sort_order[:sort_values]
  direction = @column_sort_order[:direction]

  sql_expression = '(CASE'
  sort_values.each_with_index do |value, index|
      sql_expression << " WHEN #{sort_column}=#{value} THEN #{index}"
  end
  sql_expression << " END) #{direction}" 
  sql_expression
end

#parse_sort_string ⇒ Object 



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# File 'lib/query_helper/sql_sort.rb', line 17

def parse_sort_string
  return [] if @sort_string.blank? && @sort_tiebreak.blank? && @column_sort_order.blank?

  return attributes_sql_expression(@sort_tiebreak) if @sort_string.blank?

  sql_strings = attributes_sql_expression(@sort_string)
  return sql_strings if @sort_tiebreak.blank?

  sql_strings + attributes_sql_expression(@sort_tiebreak)
end