Updated integration specs to be runnable using the ADAPTER env variable

* By default all non-adapter specific specs run with SQLite3
* Run the tasks with "ADAPTER=postgres rake spec" to run all the
  non-adapter specific specs with PostgreSQL.  Use "mysql" to test
  with the MySQL adapter.  Adding more adapters will be easy.
* Any adapter specific specs, like the MySQL, PostgreSQL and SQLite3
  specs run with their own drivers
* Fixed specs and code that failed when run with different adapters.
  There were ~10 bugs uncovered and fixed, both assumptions made in
  the specs that were untrue, or logic errors in dm-core itself
* Updated PostgreSQL driver to run with notices disabled for implicit
  actions, like automatic index creation for primary keys, not deleting
  unknown tables when DROP TABLE IF EXISTS is used, for example.

lib/data_mapper/adapters/data_objects_adapter.rb

@@ -234,16 +234,12 @@ def upgrade_model_storage(repository, model)
 
         properties = []
 
-        with_connection do |connection|
-          model.properties(name).each do |property|
-            schema_hash = property_schema_hash(property, model)
-            unless field_exists?(table_name, schema_hash[:name])
-              statement = alter_table_add_column_statement(table_name, schema_hash)
-              command = connection.create_command(statement)
-              result = command.execute_non_query
-              properties << property if result.to_i == 1
-            end
-          end
+        model.properties(name).each do |property|
+          schema_hash = property_schema_hash(property, model)
+          next if field_exists?(table_name, schema_hash[:name])
+          statement = alter_table_add_column_statement(table_name, schema_hash)
+          result = execute(statement)
+          properties << property if result.to_i == 1
         end
 
         properties
@@ -257,7 +253,6 @@ def create_model_storage(repository, model)
 
       # TODO: move to dm-more/dm-migrations
       def destroy_model_storage(repository, model)
-        return false unless storage_exists?(model.storage_name(name))
         execute(drop_table_statement(model)).to_i == 1
       end
 
@@ -640,7 +635,7 @@ def create_table_statement(model)
 
         # TODO: move to dm-more/dm-migrations
         def drop_table_statement(model)
-          "DROP TABLE #{quote_table_name(model.storage_name(name))}"
+          "DROP TABLE IF EXISTS #{quote_table_name(model.storage_name(name))}"
         end
 
         # TODO: move to dm-more/dm-migrations

lib/data_mapper/adapters/postgres_adapter.rb

@@ -52,12 +52,12 @@ def upgrade_model_storage(repository, model)
       # TODO: move to dm-more/dm-migrations
       def create_model_storage(repository, model)
         add_sequences(model)
-        super
+        without_notices { super }
       end
 
       # TODO: move to dm-more/dm-migrations
       def destroy_model_storage(repository, model)
-        success = super
+        success = without_notices { super }
         model.properties(name).each do |property|
           drop_sequence(model, property) if property.serial?
         end
@@ -74,8 +74,7 @@ def create_sequence(model, property)
 
       # TODO: move to dm-more/dm-migrations
       def drop_sequence(model, property)
-        return unless sequence_exists?(model, property)
-        execute(drop_sequence_statement(model, property))
+        without_notices { execute(drop_sequence_statement(model, property)) }
       end
 
       module SQL
@@ -85,6 +84,17 @@ def supports_returning?
           true
         end
 
+        # TODO: move to dm-more/dm-migrations
+        def without_notices(&block)
+          # execute the block with NOTICE messages disabled
+          begin
+            execute('SET client_min_messages = warning')
+            yield
+          ensure
+            execute('RESET client_min_messages')
+          end
+        end
+
         # TODO: move to dm-more/dm-migrations
         def add_sequences(model)
           model.properties(name).each do |property|
@@ -115,7 +125,7 @@ def create_sequence_statement(model, property)
 
         # TODO: move to dm-more/dm-migrations
         def drop_sequence_statement(model, property)
-          "DROP SEQUENCE #{quote_column_name(sequence_name(model, property))}"
+          "DROP SEQUENCE IF EXISTS #{quote_column_name(sequence_name(model, property))}"
         end
 
         # TODO: move to dm-more/dm-migrations

lib/data_mapper/associations/many_to_one.rb

@@ -12,11 +12,11 @@ def many_to_one(name, options = {})
         parent_model_name = options[:class_name] || DataMapper::Inflection.classify(name)
 
         relationship = relationships(repository.name)[name] = Relationship.new(
-                                                                               name,
-                                                                               repository.name,
-                                                                               self.name,
-                                                                               parent_model_name,
-                                                                               options
+          name,
+          repository.name,
+          self.name,
+          parent_model_name,
+          options
         )
 
         class_eval <<-EOS, __FILE__, __LINE__
@@ -32,7 +32,7 @@ def #{name}=(parent_resource)
 
           def #{name}_association
             @#{name}_association ||= begin
-            relationship = self.class.relationships(#{repository.name.inspect})[:#{name}]
+              relationship = self.class.relationships(#{repository.name.inspect})[:#{name}]
               association = Proxy.new(relationship, self)
               child_associations << association
               association
@@ -59,12 +59,12 @@ def save
             end
           end
         end
-        
+
         def reload!
           @parent_resource = nil
           self
         end
-        
+
         private
 
         def initialize(relationship, child_resource)

lib/data_mapper/associations/relationship.rb

@@ -23,12 +23,10 @@ def child_key
 
       def parent_key
         @parent_key ||= begin
-          model_properties = parent_model.properties(repository_name)
-
           parent_key = if @parent_properties
-            model_properties.slice(*@parent_properties)
+            parent_model.properties(repository_name).slice(*@parent_properties)
           else
-            model_properties.key
+            parent_model.key(repository_name)
           end
 
           PropertySet.new(parent_key)
@@ -44,7 +42,9 @@ def get_children(parent, options = {}, finder = :all)
       end
 
       def get_parent(child)
-        query = parent_key.to_query(child_key.get(child))
+        bind_values = child_key.get(child)
+        return nil if bind_values.any? { |bind_value| bind_value.nil? }
+        query = parent_key.to_query(bind_values)
 
         DataMapper.repository(repository_name) do
           parent_model.first(query.merge(@query))

lib/data_mapper/property_set.rb

@@ -92,8 +92,8 @@ def lazy_load_context(names)
       result
     end
 
-    def to_query(values)
-      Hash[ *zip(values).flatten ]
+    def to_query(bind_values)
+      Hash[ *zip(bind_values).flatten ]
     end
 
     def inspect

lib/data_mapper/repository.rb

@@ -88,7 +88,7 @@ def save(resource)
       # set defaults for new resource
       if resource.new_record?
         model.properties(name).each do |property|
-          next if property.default.nil? || resource.attribute_loaded?(property.name)
+          next if resource.attribute_loaded?(property.name)
           property.set(resource, property.default_for(resource))
         end
       end

lib/data_mapper/resource.rb

@@ -71,7 +71,10 @@ def attribute_set(name, value)
       old_value = instance_variable_get(ivar_name)
       new_value = property.custom? ? property.type.dump(value, property) : property.typecast(value)
 
-      return if old_value == new_value
+      # skip setting the attribute if the new value equals the old
+      # value, or if the new value is nil, and the property does not
+      # allow nil values
+      return if new_value == old_value || (new_value.nil? && !property.nullable?)
 
       if property.lock?
         instance_variable_set("@shadow_#{name}", old_value)

script/all

@@ -1,4 +1,5 @@
 #!/usr/bin/env sh
+rake spec:unit
 ADAPTER=sqlite3  rake spec:integration
 ADAPTER=mysql    rake spec:integration
 ADAPTER=postgres rake spec:integration