Freezing composite primary key so that we can apply TomH's patch to it, and that...

[rails.git] / vendor / gems / composite_primary_keys-1.1.0 / lib / composite_primary_keys / calculations.rb

diff --git a/vendor/gems/composite_primary_keys-1.1.0/lib/composite_primary_keys/calculations.rb b/vendor/gems/composite_primary_keys-1.1.0/lib/composite_primary_keys/calculations.rb
new file mode 100644 (file)
index 0000000..44280e1
--- /dev/null
+++ b/vendor/gems/composite_primary_keys-1.1.0/lib/composite_primary_keys/calculations.rb
@@ -0,0 +1,68 @@
+module CompositePrimaryKeys
+  module ActiveRecord
+    module Calculations
+      def self.append_features(base)
+        super
+        base.send(:extend, ClassMethods)
+      end
+
+      module ClassMethods
+        def construct_calculation_sql(operation, column_name, options) #:nodoc:
+          operation = operation.to_s.downcase
+          options = options.symbolize_keys
+
+          scope           = scope(:find)
+          merged_includes = merge_includes(scope ? scope[:include] : [], options[:include])
+          aggregate_alias = column_alias_for(operation, column_name)
+          use_workaround  = !connection.supports_count_distinct? && options[:distinct] && operation.to_s.downcase == 'count'
+          join_dependency = nil
+
+          if merged_includes.any? && operation.to_s.downcase == 'count'
+            options[:distinct] = true
+            use_workaround  = !connection.supports_count_distinct?
+            column_name = options[:select] || primary_key.map{ |part| "#{quoted_table_name}.#{connection.quote_column_name(part)}"}.join(',')
+          end
+
+          sql  = "SELECT #{operation}(#{'DISTINCT ' if options[:distinct]}#{column_name}) AS #{aggregate_alias}"
+
+          # A (slower) workaround if we're using a backend, like sqlite, that doesn't support COUNT DISTINCT.
+          sql = "SELECT COUNT(*) AS #{aggregate_alias}" if use_workaround
+
+          sql << ", #{connection.quote_column_name(options[:group_field])} AS #{options[:group_alias]}" if options[:group]
+          sql << " FROM (SELECT DISTINCT #{column_name}" if use_workaround
+          sql << " FROM #{quoted_table_name} "
+          if merged_includes.any?
+            join_dependency = ::ActiveRecord::Associations::ClassMethods::JoinDependency.new(self, merged_includes, options[:joins])
+            sql << join_dependency.join_associations.collect{|join| join.association_join }.join
+          end
+          add_joins!(sql, options, scope)
+          add_conditions!(sql, options[:conditions], scope)
+          add_limited_ids_condition!(sql, options, join_dependency) if \
+            join_dependency &&
+            !using_limitable_reflections?(join_dependency.reflections) &&
+            ((scope && scope[:limit]) || options[:limit])
+
+          if options[:group]
+            group_key = connection.adapter_name == 'FrontBase' ?  :group_alias : :group_field
+            sql << " GROUP BY #{connection.quote_column_name(options[group_key])} "
+          end
+
+          if options[:group] && options[:having]
+            # FrontBase requires identifiers in the HAVING clause and chokes on function calls
+            if connection.adapter_name == 'FrontBase'
+              options[:having].downcase!
+              options[:having].gsub!(/#{operation}\s*\(\s*#{column_name}\s*\)/, aggregate_alias)
+            end
+
+            sql << " HAVING #{options[:having]} "
+          end
+
+          sql << " ORDER BY #{options[:order]} " if options[:order]
+          add_limit!(sql, options, scope)
+          sql << ') w1' if use_workaround # assign a dummy table name as required for postgresql
+          sql
+        end
+      end
+    end
+  end
+end