Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>Hi I saw your post and thought I may give you my opion. First I must say I've been doing DDD in project for three years now, so I'm not an expert. But I'm currently working in a project as an architect an coaching developers in DDD, and I must say it isn't a walk in the park... I don't know how many times I've refactored the model and Entity relationships.</p> <p>But my experience is that you endup with some repositories (more than few but not many). My Aggregates usually contains a few classes and the Aggregate object graph isn't that deep (if you know what I mean). </p> <p>But I try to be concrete:</p> <p>1) Aggregate roots are defined by your needs. I mean if you feel that you need that Tasks object through Journal to often, then maybe thats a sign for it to be upgraded as a aggregate root.</p> <p>2) But everything cannot be aggregate roots, so try to capsulate object that are tight related. Notes seems like a candidate for being own by a root object. You'd probably always relate Notes to the root or it loses its context. Notes cannot live by itself. </p> <p>3) Remember that Aggregates are used for splitting up large complex domains into smaller "islands" that take care of thier inhabbitants. Its important to not make your domain more complex than it is.</p> <p>4) You don't know how your model look likes before you've reached far into the project implementation phase. If you realize that some repositories aren't used that much, they may be candidates for merging into other root object (if they have that kind of relationship). You can break out objects that are used so much through root object without its context. I mean for example if Journal are aggregate root and contains Notes and Tasks. After a while you model grows and maybe Tasks have assoications to Action and ActionHistory and User and Rule and Permission. Now I just throw out a bunch om common objects in a rule/action/user permission functionality. Maybe this result in usecases that approach Tasks from another angle, "View all Tasks performed by this User" etc. Tasks get more involved in some kind of State/Workflow engine and therefor candidates for being an aggregate root itself. </p> <p>Okey. Not the best example but it maybe gives you the idea. A root object can contain children where some of its children can also be root object because we need it in another context (than journal). But I have myself banged my head against the wall everytime you startup with a fresh model. Just go with the flow and let the model evolve itself through its clients/subsribers. You refine the model through its usage. The Services (application services and not domain services) are of course extended with methods that respond to UI and usecases (often one-to-one). </p> <p>I hope I helped you in someway...or not :D</p>
    singulars
    1. This table or related slice is empty.
    1. POAggregate roots depend on the use case so does that mean that we might end up with really a lots of repositories?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. This table or related slice is empty.
    1. USMagnus Backeus
    plurals
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. This table or related slice is empty.
    1. VO
      singulars
      1. PO
      1. This table or related slice is empty.
      1. VTUpMod
    1. This table or related slice is empty.
 

Querying!

 
Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload