Module: Prioritize::PriorityAfter::ClassMethods

Defined in:
lib/prioritize.rb

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Instance Attribute Details

#priority_column ⇒ Object

Returns the value of attribute priority_column.



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# File 'lib/prioritize.rb', line 65

def priority_column
  @priority_column
end

Class Method Details

.extended(base) ⇒ Object 



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# File 'lib/prioritize.rb', line 69

def self.extended base
  base.class_eval do
    @priority_column = :priority
  end
end

Instance Method Details

#priority_after(before_id, moved_id) ⇒ Object 



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# File 'lib/prioritize.rb', line 24

def priority_after before_id, moved_id
  connection.exec_query(
    <<-SQL,
      UPDATE #{table_name} o
      SET #{priority_column} = ordered.rn
      FROM (
        SELECT *, ROW_NUMBER() OVER() AS rn
        FROM (
          (
            SELECT o.*
            FROM #{table_name} o
            LEFT JOIN #{table_name} ai ON ai.id = $1
            WHERE
              (o.#{priority_column} < ai.#{priority_column} OR ai.#{priority_column} IS NULL) AND
              o.id <> $2
            ORDER BY o.#{priority_column} ASC
          )
          UNION ALL
          (
            SELECT o.*
            FROM #{table_name} o
            WHERE o.id = $2
          )
          UNION ALL
          (
            SELECT o.*
            FROM #{table_name} o
            LEFT JOIN #{table_name} ai ON ai.id = $1
            WHERE
              o.#{priority_column} >= ai.#{priority_column} AND
              o.id <> $2
            ORDER BY o.#{priority_column} ASC
          )
        ) numbered
      ) ordered
      WHERE  o.id = ordered.id
    SQL
    'priority_after',
    [[nil,before_id], [nil,moved_id]]
  )
end