Comments on: Life inside an Aggregate Root, part 1 http://richarddingwall.name/2009/10/13/life-inside-an-aggregate-root-part-1/ Adventures of a young kiwi software developer in London Tue, 09 Mar 2010 23:02:54 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Jaime Metcher http://richarddingwall.name/2009/10/13/life-inside-an-aggregate-root-part-1/comment-page-1/#comment-12504 Jaime Metcher Thu, 28 Jan 2010 00:54:33 +0000 http://richarddingwall.name/?p=2194#comment-12504 I don't really have a problem with the backreference from SkillGroup to TrainingProgramme, but having a method TrainingProgramme.addSkill(skillGroup,skill) that does the uniqueness check before calling skillGroup.add(skill) seems to me to be putting the responsibility where it belongs. The requirement for whole of programme skill uniqueness is part of the specification of TrainingProgramme, and yet it's being implemented by SkillGroup. To put it another way, looking at the code of TrainingProgramme would not tell you that requirement existed. I don’t really have a problem with the backreference from SkillGroup to TrainingProgramme, but having a method TrainingProgramme.addSkill(skillGroup,skill) that does the uniqueness check before calling skillGroup.add(skill) seems to me to be putting the responsibility where it belongs. The requirement for whole of programme skill uniqueness is part of the specification of TrainingProgramme, and yet it’s being implemented by SkillGroup. To put it another way, looking at the code of TrainingProgramme would not tell you that requirement existed.

]]> By: Reflective Perspective - Chris Alcock » The Morning Brew #454 http://richarddingwall.name/2009/10/13/life-inside-an-aggregate-root-part-1/comment-page-1/#comment-10963 Reflective Perspective - Chris Alcock » The Morning Brew #454 Wed, 14 Oct 2009 07:47:42 +0000 http://richarddingwall.name/?p=2194#comment-10963 [...] Life inside an Aggregate Root, part 1 - Richard Dingwall explores one of the key Domain Driven Design tenants, the ‘aggregate root’ in this two part article discussing the key rules about how they should behave [...] [...] Life inside an Aggregate Root, part 1 – Richard Dingwall explores one of the key Domain Driven Design tenants, the ‘aggregate root’ in this two part article discussing the key rules about how they should behave [...]

]]> By: Richard Dingwall » Life inside an Aggregate Root, part 2 http://richarddingwall.name/2009/10/13/life-inside-an-aggregate-root-part-1/comment-page-1/#comment-10952 Richard Dingwall » Life inside an Aggregate Root, part 2 Tue, 13 Oct 2009 20:13:23 +0000 http://richarddingwall.name/?p=2194#comment-10952 [...] This is the second half of a two-part article. Read the first half here: Life inside an Aggregate Root, part 1. [...] [...] This is the second half of a two-part article. Read the first half here: Life inside an Aggregate Root, part 1. [...]

]]> By: Richard http://richarddingwall.name/2009/10/13/life-inside-an-aggregate-root-part-1/comment-page-1/#comment-10933 Richard Mon, 12 Oct 2009 23:58:40 +0000 http://richarddingwall.name/?p=2194#comment-10933 Kevin: good question - I inject the aggregate root into the entity when it is constructed i.e., when you create a SkillGroup, you specify which TrainingProgramme it belongs to (see example). If you're using NHibernate, the TrainingProgramme->SkillGroup association is inverse. Part 2 will be about making the TrainingProgramme responsible for constructing child SkillGroups :) Kevin: good question – I inject the aggregate root into the entity when it is constructed i.e., when you create a SkillGroup, you specify which TrainingProgramme it belongs to (see example). If you’re using NHibernate, the TrainingProgramme->SkillGroup association is inverse.

Part 2 will be about making the TrainingProgramme responsible for constructing child SkillGroups :)

]]> By: Kevin Berridge http://richarddingwall.name/2009/10/13/life-inside-an-aggregate-root-part-1/comment-page-1/#comment-10931 Kevin Berridge Mon, 12 Oct 2009 23:31:16 +0000 http://richarddingwall.name/?p=2194#comment-10931 Not sure if you're planning on covering this in a future post, but I'm curious. If you were using NHibernate (or any ORM really), how would you set the back pointer from SkillGroup to TrainingProgramme? I'm assuming the ORM wouldn't know how to do this for you, so you would have to intercede at some point. Not sure if you’re planning on covering this in a future post, but I’m curious. If you were using NHibernate (or any ORM really), how would you set the back pointer from SkillGroup to TrainingProgramme? I’m assuming the ORM wouldn’t know how to do this for you, so you would have to intercede at some point.

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