Module: OrderAsSpecified
- Defined in:
- lib/order_as_specified.rb,
lib/order_as_specified/error.rb,
lib/order_as_specified/version.rb
Overview
This module adds the ability to query an ActiveRecord class for results from the database in an arbitrary order, without having to store anything extra in the database. Simply ‘extend` it into your class and then you can use the `order_as_specified` class method.
Defined Under Namespace
Classes: Error
Constant Summary collapse
- VERSION =
"1.7"
Instance Method Summary collapse
-
#order_as_specified(hash) ⇒ ActiveRecord::Relation
The objects, ordered as specified.
Instance Method Details
#order_as_specified(hash) ⇒ ActiveRecord::Relation
Returns the objects, ordered as specified.
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# File 'lib/order_as_specified.rb', line 13 def order_as_specified(hash) distinct_on = hash.delete(:distinct_on) case_insensitive = hash.delete(:case_insensitive) params = extract_params(hash) return all if params[:values].empty? table = Arel::Table.new(params[:table]) node = Arel::Nodes::Case.new params[:values].each_with_index do |value, index| attribute = table[params[:attribute]] condition = if value.is_a?(Range) if value.first >= value.last raise OrderAsSpecified::Error, "Range needs to be increasing" end attribute.between(value) elsif case_insensitive attribute.matches(value) else attribute.eq(value) end node.when(condition).then(index) end node.else(node.conditions.size) scope = order(Arel::Nodes::Ascending.new(table.grouping(node))) if distinct_on distinct = Arel::Nodes::DistinctOn.new(node) table_alias = connection.quote_table_name(table.name) scope = scope.select(Arel.sql("#{distinct.to_sql} #{table_alias}.*")) end scope end |