Add support for touch

.gitignore

@@ -8,5 +8,7 @@ db
 
 /doc
 /.idea
+*.swo
+*.swp
 
 test/connections/databases.yml

lib/composite_primary_keys/persistence.rb

@@ -35,6 +35,35 @@ def destroy
       freeze
     end
 
+    def touch(name = nil)
+      attributes = timestamp_attributes_for_update_in_model
+      attributes << name if name
+
+      unless attributes.empty?
+        current_time = current_time_from_proper_timezone
+        changes = {}
+
+        attributes.each do |column|
+          column = column.to_s
+          changes[column] = write_attribute(column, current_time)
+        end
+
+        changes[self.class.locking_column] = increment_lock if locking_enabled?
+
+        puts changes.inspect
+
+        @changed_attributes.except!(*changes.keys)
+
+        relation    = self.class.send(:relation)
+        arel_table  = self.class.arel_table
+        primary_key = self.class.primary_key
+
+        primary_key_predicate = relation.cpk_id_predicate(arel_table, Array(primary_key), Array(id))
+
+        self.class.unscoped.where(primary_key_predicate).update_all(changes) == 1
+      end
+    end
+
     def update(attribute_names = @attributes.keys)
       klass = self.class
       if !self.composite?
@@ -56,4 +85,4 @@ def update(attribute_names = @attributes.keys)
       klass.connection.update stmt.to_sql
     end
   end
-end
+end

test/fixtures/db_definitions/postgresql.sql

@@ -18,14 +18,18 @@ create table reference_codes (
 create table products (
     id serial not null,
     name varchar(50) default null,
-    primary key (id)
+    primary key (id),
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL
 );
 
 create table tariffs (
     tariff_id  int  not null,
     start_date date not null,
     amount     int  default null,
-    primary key (tariff_id, start_date)
+    primary key (tariff_id, start_date),
+    created_at timestamp without time zone NOT NULL,
+    updated_at timestamp without time zone NOT NULL
 );
 
 create table product_tariffs (

test/fixtures/db_definitions/sqlite.sql

@@ -16,13 +16,17 @@ create table reference_codes (
 
 create table products (
     id int(11) not null primary key,
-    name varchar(50) default null
+    name varchar(50) default null,
+    created_at TIMESTAMP,
+    updated_at TIMESTAMP
 );
 
 create table tariffs (
     tariff_id int(11) not null,
     start_date date not null,
     amount integer(11) default null,
+    created_at TIMESTAMP,
+    updated_at TIMESTAMP,
     primary key (tariff_id, start_date)
 );
 

test/test_touch.rb

@@ -0,0 +1,23 @@
+# Test cases devised by Santiago that broke the Composite Primary Keys
+# code at one point in time. But no more!!!
+require File.expand_path('../abstract_unit', __FILE__)
+
+class TestTouch < ActiveSupport::TestCase
+  fixtures :products, :tariffs
+
+  def test_touching_a_record_updates_its_timestamp
+    tariff                = tariffs(:flat)
+    previous_amount       = tariff.amount
+    previously_updated_at = tariff.updated_at
+
+    tariff.amount         = previous_amount + 1
+    tariff.touch
+
+    assert_not_equal previously_updated_at, tariff.updated_at
+    assert_equal previous_amount + 1, tariff.amount
+    assert tariff.amount_changed?, 'tarif amount should have changed'
+    assert tariff.changed?, 'tarif should be marked as changed'
+    tariff.reload
+    assert_not_equal previously_updated_at, tariff.updated_at
+  end
+end