Best way to update groups of aggregate roots question

Tue, 03/16/2010 - 13:57 — JRodman

I have a scenario where I have an aggregate root called "Project". Each project is in a specific order based on a DisplayOrder property which is basically an integer. There is no entity above a project that would be better suited as the aggregate root. What is the proper way to model the behavior to change the order of a project in relation to all other projects?

The logic to accomplish this is simple. Change the order of the project being moved by calling its SetOrder() method, and update the order of all the other projects around that need to be pushed down to make it fit by using the same method on each. Then they would all need to be saved as a group to guarantee consistency.

Here is the line of thinking we have had so far, and the two solutions we are trying to decide on:

1. Create an aggregate to represent all the projects as a "List".

This would create the concept of a "ProjectList" aggregate root which simply has a "MoveProject" method to take a project from one position in the list and move it, but can be saved as a whole using a repository. I believe this is a bad approach because it seems like we are manufacturing an aggregate that isn't really an entity and has no identity just to model a behavior.

2. Use a domain service.

This would create a "ProjectOrderingService" that has a method called "MoveProject" that would take the project to move and would be responsible for loading all the projects, reorder them and save them using the ProjectRepository. I favor this approach since it seems like a perfect fit for a domain service. Members of my team don't like this since it requires the service to access repositories to retrieve and save the projects, but to me this is perfectly allowed since the implementation of the service would be in the infrastructure layer.

Which approach is most in line with DDD priciples, or is there another approach that is better suited to this need?

Site feedback

Login or register to post comments
1352 reads

Sat, 07/31/2010 - 05:07 — roalno

The most recommended best

The most recommended best rain barrel is algreen 81001 which is most popular in garden and algreen 81002, algreen 81111 which is look like a vase and algreen 81112 black edition.

Fri, 07/30/2010 - 09:47 — ram

Very impressive. Keep writing

Very impressive. Keep writing more informative information. Thanks! Reusable Ice packs

Thu, 07/29/2010 - 18:16 — michaelroy1

Thank You for taking your

Thank You for taking your time to discuss this, I feel strongly about it and will love to learning more on this at future. If possible, as you gain expertise, would you mind updating your blog with more useful informations? Honestly It is very helpful for me . fertility

Thu, 07/29/2010 - 18:09 — christmassms

I was looking for crucial

I was looking for crucial information on this subject. The information was important as I am about to launch my own portal. Thanks for providing a missing link in my business. Wholesale Food

Thu, 07/29/2010 - 17:59 — christmassms

When I read this post it

When I read this post it reminds me of my old room mate! He always kept talking about this. I will forward this article to him. Pretty sure he will have a good read. Thanks for sharing! web development

Thu, 07/29/2010 - 17:38 — michaelroy1

Cosmetics should be used

Cosmetics should be used carefully on the skin because these may cause allergic reactions. Each season requires suitable clothing in order to facilitate the evaporation of the sweat. Sunlight, water and air play an important role in keeping the skin healthy. Gucci Sunglasses

Thu, 07/29/2010 - 09:47 — KarenG

Thanks

Wow. This blog is truly a gold mine. I have been wallowing on this for quite sometime and here I am reading about it! I will actually try these tips and let you know how they work out! Thanks again mate. drug treatment center

Thu, 07/29/2010 - 03:33 — nike22

rosetta stone

I really like the style of your writing.rosetta stone spanish, I found your blog on bing and decided to check out.rosetta stone, I want to say very thank you for this great informations. now i understand about it. Thank you ! rosetta stone sale, discount rosetta stone, rosetta stone software, rosetta stone french. rosetta stone language. rosetta stone german. buy rosetta stone

—

nike22

Thu, 07/29/2010 - 03:26 — jibran_pcc

What a fantabulous post this

What a fantabulous post this has been. Never seen this kind of useful post. I am grateful to you and expect more number of posts like these. Thank you very much. Cheap Auto Insurance

—

Jibran Ayub

Wed, 07/28/2010 - 21:06 — mackliy

MBT shoe is anti-shoe,Factory

MBT shoe is anti-shoe,Factory Direct, Top Quality. 60% OFF,$85 ONLY.MBT would like to help people around the world live more active, healthier and happier lives. mbt shoes canada to awaken and strengthen the awareness of physiologically correct walking by publicizing the idea and concept of coach bags on sale. They will not only change the way you use your muscles, but also will improve the use of your joints and spine. mbt shoes sale promotion has been launched.

Wed, 07/28/2010 - 01:56 — ram

They provide controlled and

They provide controlled and directed access to composite entities. They can enforce rules to ensure that the entire aggregate is valid. oracle trader

Tue, 07/27/2010 - 05:07 — mingqi001

If you are nfl jerseys fans,

If you are nfl jerseys fans, don’t miss to buy cheap authentic NFL Jerseys here nfl store, 2010 new style nfl football jerseys on hot sale!

—

If you are nfl jerseys fans, don’t miss to buy cheap authentic NFL Jerseys here nfl store.

Tue, 07/27/2010 - 02:23 — anlia

nothing is impossible.

Thanks for your sharing, good job! Are you interested in the gucci jeans series? Topguccishoes.com will be the right place that you have come to. There are many different kinds products of gucci outlet for your selection, including gucci handbags, gucci sneakers which content with gucci men shoes, Gucci Trousers, Gucci Skirt, gucci bikini , gucci belts, Gucci Spicy Underwear, Gucci Wallets, Gucci Jewelry, gucci hats, gucci sunglasses and Women Gucci boots line. Welcome to the discount gucci handbags and buy discount gucci shoes with the best quality at affordable price.

Mon, 07/26/2010 - 19:11 — johngate2100

Difficult question

You are asking some thing which is very difficult to answer but i could recommend to to contact these links then you will find the best answer i hope so. Like there are three links which you can find it out here. packaging boxes packaging supplies retail packaging.If you click any one of these.You will find the best answer if fyou contact their site manager.Thanks.

—

retail packaging

Mon, 07/26/2010 - 10:29 — harsh7

This is nice post which I was

This is nice post which I was awaiting for such an artice and I have gained some useful information from this site. Thanks for sharing this information.. care2takers

Mon, 07/26/2010 - 08:15 — spincalis3

The blog was absolutely

The blog was absolutely fantastic! Lots of great information and inspiration, both of which we all need! natural tinnitus cures

Sat, 07/24/2010 - 04:55 — mikegxf

COOKWARE

Sat, 07/24/2010 - 02:55 — joshua2930

Keep up the good work. online

Keep up the good work. online phd degree | degree

Sat, 07/24/2010 - 02:55 — joshua2930

Thanks for sharing

Thanks for sharing this. online bachelors degree | online masters degree | online doctorate degree

Thu, 07/22/2010 - 22:29 — Hochfart

For most couples who are

For most couples who are planning their wedding, prom dressespaying particular attention to the wedding flowers is just as essential as choosing the design of the wedding attire for both groom and bride. affordable bridesmaid dressesAfter all, flowers lit up the wedding venue, enhance the bride's looks and brighten up every table during the wedding reception. hair extensionsFlowers are also included in the wedding tradition of "throwing the bouquet" which through time has been known to give everyone an idea who the next bride is going to be. When couples choose what kind of flowers they will use for their wedding day, the usual choice is the orchid. wedding invitationsSince orchids come in different colors and varieties,cheap prom dresses they can very well match the motif that is chosen for the bridal gown and the wedding venue decorations. Orchid blooms that are used to decorate the church as well as the reception area provide that elegance that is most welcome during this occasion. hair extensionIt seems to tell everyone that love is in the air, as the newly married couple celebrates their vows in front of their family and friends.wedding hairstyles

Fri, 07/23/2010 - 05:25 — mikegxf

I like the river boat Home

I like the river boat Home GYM equipment gym idea. running machine A more basic idea that might work though fitness treadmill equipment would be hooking dynamo’ home gym s up to all the eliptical, Home treadmill treadmill, treadmill machineand byclces at the gym and harnessing that electrical power for use by the gym. I would totallyCommercial treadmill get a membership if the River boat gym Treadmill equipmentevery opens a fitness treadmilllocationElectric treadmill on Ladybird motorized treadmilllake and would definitely tryexercise treadmill to run over folding treadmill the crew teams. Garden Machines haha no hard Gardening Power Tools feelings cookware sets crew members. crew members.nonstick cookware setware set

Thu, 07/22/2010 - 21:09 — dress

how awful

2010 new styles A-line Wedding Dresses,Beach Wedding Dresses,Evening Dresses,Prom Dresses on sale evening dresses Prom dresses wedding dresses on best wedding dresses for 2009 and 2010. You can find latest collection of woman's dresses and casual dresses on this site discount Prom dresses discount wedding dresses a series of discount Wedding Dresses, Including Wedding gowns, Evening gowns, Wedding Dress, Bridal gowns and Bridal Dress wedding dresses prom dresses Look more beautiful than you've ever imagined in top designer dresses

Thu, 07/22/2010 - 01:49 — sskkyy88

We have the latest coach bags

We have the latest coach bags Kristin collection sale at online. The coach outlet line is clean and effortless, it still as other handbags have high quality. The coach outlet store of the handbags are soft and elegant. Shades of coral, pink, ivory, and burnished amber this entire are makes us feel comfortable. Though made from simple leather, the handbags have many optimum dimension and appeal, as well as fresh flush blocking, embossed exotics, and rich glazed leather. This durable Kristin coach handbags coach outlet store online be assured of its durability and long life.

Fri, 04/09/2010 - 17:08 — ormsky

other possibilities?

Does this integer value actually need to be a property in the domain entity? It sounds more like an implementation value rather than an instrinsic property of a "Project" (although I obviously do not know the domain). In which case two other possibilities could be:

1) Move responsibility to the "Project" entities repository where you can optimise the code that does the ordering into the repository implementation; define the methods you require in the repository interface to both re-order entities and fetch entities as an ordered list.

2) Have a new "OrderedProjectsCollection" entity. This could be more flexible in that you could create different ordered lists (but would need a different structure to your database).

Domain-Driven Design Community

Navigation

User login