0
@@ -228,6 +228,7 @@ module DataMapper
0
           statement << " FROM #{quote_table_name(query.model.storage_name(query.repository.name))}"
0
           statement << links_statement(query)                        if query.links.any?
0
           statement << " WHERE #{conditions_statement(query)}"       if query.conditions.any?
0
+          statement << " GROUP BY #{group_by_statement(query)}"      if query.unique?
0
           statement << " ORDER BY #{order_statement(query)}"         if query.order.any?
0
           statement << " LIMIT #{quote_column_value(query.limit)}"   if query.limit
0
           statement << " OFFSET #{quote_column_value(query.offset)}" if query.offset && query.offset > 0
0
@@ -317,6 +318,18 @@ module DataMapper
0
           end * ', '
0
         end
0
 
0
+        def group_by_statement(query)
0
+          if query.unique?
0
+            query.fields.map do |field|
0
+              property_to_column_name(query.repository, field, true)
0
+            end.join(", ")
0
+          elsif query.group_by
0
+            query.group_by.map do |field|
0
+              property_to_column_name(query.repository, field, true)
0
+            end.join(", ")
0
+          end
0
+        end
0
+
0
         def condition_statement(query, operator, left_condition, right_condition)
0
           return left_condition if operator == :raw
0
 

0
@@ -19,12 +19,13 @@ module DataMapper
0
       def get_children(parent, options = {}, finder = :all, *args)
0
         query = @query.merge(options).merge(child_key.to_query(parent_key.get(parent)))
0
 
0
-        query[:links] = links
0
+        query[:links]  = links
0
+        query[:unique] = true
0
 
0
         with_repository(parent) do
0
           results = grandchild_model.send(finder, *(args << query))
0
           # FIXME: remove the need for the uniq.freeze
0
-          finder == :all ? (@mutable ? results.uniq : results.uniq.freeze) : results
0
+          finder == :all ? (@mutable ? results : results.freeze) : results
0
         end
0
       end
0
 

0
@@ -3,10 +3,10 @@ module DataMapper
0
     include Assertions
0
 
0
     OPTIONS = [
0
-      :reload, :offset, :limit, :order, :add_reversed, :fields, :links, :includes, :conditions
0
+      :reload, :offset, :limit, :order, :add_reversed, :fields, :links, :includes, :conditions, :unique, :group_by
0
     ]
0
 
0
-    attr_reader :repository, :model, *OPTIONS - [ :reload ]
0
+    attr_reader :repository, :model, *OPTIONS - [ :reload, :unique ]
0
     attr_writer :add_reversed
0
     alias add_reversed? add_reversed
0
 
0
@@ -14,6 +14,10 @@ module DataMapper
0
       @reload
0
     end
0
 
0
+    def unique?
0
+      @unique
0
+    end
0
+
0
     def reverse
0
       dup.reverse!
0
     end
0
@@ -42,6 +46,7 @@ module DataMapper
0
 
0
       # only overwrite the attributes with non-default values
0
       @reload       = other.reload?       unless other.reload?       == false
0
+      @unique       = other.unique?       unless other.unique?       == false
0
       @offset       = other.offset        unless other.offset        == 0
0
       @limit        = other.limit         unless other.limit         == nil
0
       @order        = other.order         unless other.order         == model.default_order
0
@@ -67,6 +72,7 @@ module DataMapper
0
       #   return hash == other.hash
0
       @model        == other.model         &&
0
       @reload       == other.reload?       &&
0
+      @unique       == other.unique?       &&
0
       @offset       == other.offset        &&
0
       @limit        == other.limit         &&
0
       @order        == other.order         &&  # order is significant, so do not sort this
0
@@ -136,6 +142,7 @@ module DataMapper
0
         [ :limit,      limit           ],
0
         [ :offset,     offset          ],
0
         [ :reload,     reload?         ],
0
+        [ :unique,     unique?         ],
0
       ]
0
 
0
       "#<#{self.class.name} #{attrs.map { |(k,v)| "@#{k}=#{v.inspect}" } * ' '}>"
0
@@ -157,6 +164,7 @@ module DataMapper
0
 
0
       @model        = model                               # must be Class that includes DM::Resource
0
       @reload       = options.fetch :reload,       false  # must be true or false
0
+      @unique       = options.fetch :unique,       false  # must be true or false
0
       @offset       = options.fetch :offset,       0      # must be an Integer greater than or equal to 0
0
       @limit        = options.fetch :limit,        nil    # must be an Integer greater than or equal to 1
0
       @order        = options.fetch :order,        model.default_order   # must be an Array of Symbol, DM::Query::Direction or DM::Property
0
@@ -164,6 +172,7 @@ module DataMapper
0
       @fields       = options.fetch :fields,       @properties.defaults  # must be an Array of Symbol, String or DM::Property
0
       @links        = options.fetch :links,        []     # must be an Array of Tuples - Tuple [DM::Query,DM::Assoc::Relationship]
0
       @includes     = options.fetch :includes,     []     # must be an Array of DM::Query::Path
0
+      @group_by     = options.fetch :group_by,     nil    # must be a an Array of Symbol, String or DM::Property
0
       @conditions   = []                                  # must be an Array of triplets (or pairs when passing in raw String queries)
0
 
0
       # normalize order and fields
0
@@ -223,9 +232,11 @@ module DataMapper
0
 
0
     # validate the options
0
     def assert_valid_options(options)
0
-      # validate the reload option
0
-      if options.has_key?(:reload) && options[:reload] != true && options[:reload] != false
0
-        raise ArgumentError, "+options[:reload]+ must be true or false, but was #{options[:reload].inspect}", caller(2)
0
+      # validate the reload option & unique option
0
+      ([ :reload, :unique ] & options.keys).each do |attribute|
0
+        if options[attribute] != true && options[attribute] != false
0
+          raise ArgumentError, "+options[:#{attribute}]+ must be true or false, but was #{options[attribute].inspect}", caller(2)
0
+        end
0
       end
0
 
0
       # validate the offset and limit options

0
@@ -136,7 +136,6 @@ if ADAPTER
0
     end
0
 
0
     it 'should handle get()' do
0
-      pending "Collection#uniq isn't implemented, see lib/dm-core/associations/relationship_chain.rb:27"
0
       post = Post.get!(2)
0
       related_posts = Post.first.related_posts
0
       related_posts.get(2).should == post