I'm trying to create a small forum application using Symfony 2 and Doctrine 2. My ForumTopic entity has a last_post field (oneToOne mapping). Now when I persist my new post with $em->persist($post); I want to update my ForumTopic entity so its last_post field would reference this new post. I have just realised that it cannot be done with a Doctrine postPersist Listener, so I decided to use a small hack, and tried: $em->persist($post); $em->flush(); $topic->setLastPost($post); $em->persist($post); $em->flush(); but it doesn't seem to update my topics table. I also took a look at http://docs.doctrine-project.org/projects/doctrine-orm/en/2.1/reference/working-with-associations.html#transitive-persistence-cascade-operations hoping it will solve the problem by adding cascade: [ 'persist' ] to my Topic.orm.yml file, but it didn't help, either. Could anyone point me to a solution or an example class? My ForumTopic is: FrontBundle\Entity\ForumTopic: type: entity table: forum_topics id: id: type: integer generator: strategy: AUTO fields: title: type: string(100) nullable: false slug: type: string(100) nullable: false created_at: type: datetime nullable: false updated_at: type: datetime nullable: true update_reason: type: text nullable: true oneToMany: posts: targetEntity: ForumPost mappedBy: topic manyToOne: created_by: targetEntity: User inversedBy: articles nullable: false updated_by: targetEntity: User nullable: true default: null topic_group: targetEntity: ForumTopicGroup inversedBy: topics nullable: false oneToOne: last_post: targetEntity: ForumPost nullable: true default: null cascade: [ persist ] uniqueConstraint: uniqueSlugByGroup: columns: [ topic_group, slug ] And my ForumPost is: FrontBundle\Entity\ForumPost: type: entity table: forum_posts id: id: type: integer generator: strategy: AUTO fields: created_at: type: datetime nullable: false updated_at: type: datetime nullable: true update_reason: type: string nullable: true text: type: text nullable: false manyToOne: created_by: targetEntity: User inversedBy: forum_posts nullable: false updated_by: targetEntity: User nullable: true default: null topic: targetEntity: ForumTopic inversedBy: posts