Databases
StackOverflow2013
Postsdbo
PO
 

Note that there are some explanatory texts on larger screens.

plurals
  1. PO
    primarykey
    data
    text
    <p>I think <em>willbt</em> has given you a really good <a href="https://stackoverflow.com/questions/1517033/how-to-implement-the-query-side-of-cqs-in-ddd/1549669#1549669">starting point</a>.</p> <p>I would add that if you do opt to continue to use the ORM as the data-access strategy for queries you would be well-advised to consider defining a fetching strategy tailored to the data you expect you'll need to access (I'm thinking specifically about NHibernate here, by the way). What this means is you can decide whether to lazy-load or to eager-load the objects and collections associated with a particular <a href="http://dddstepbystep.com/wikis/ddd/aggregate-root.aspx" rel="nofollow noreferrer">Aggregate Root</a> object.</p> <p>The <a href="http://github.com/riteshrao/ncommon" rel="nofollow noreferrer">NCommon project</a> by Ritesh Rao offers an excellent (work in progress) demonstration of how to define a different fetching strategy for different purposes.</p> <p>Ritesh <a href="http://www.codeinsanity.com/2009/02/fetching-strategy-and-adaptive-domain.html" rel="nofollow noreferrer">explains it really</a> well in his blog.</p> <p>Go ahead and have a look at the source:</p> <ul> <li>here's <a href="http://github.com/riteshrao/ncommon/blob/master/NCommon/src/Data/IFetchingStrategy.cs" rel="nofollow noreferrer">the IFetchingStrategy interface</a></li> <li>and this shows <a href="http://github.com/riteshrao/ncommon/blob/master/NCommon.NHibernate/tests/NHRepositoryTests.cs" rel="nofollow noreferrer">the use of fetching strategies in a unit test</a></li> </ul> <p>In the test 'Repository_For_Uses_Registered_Fetching_Strategies' the call to </p> <pre><code>NHRepository&lt;Order&gt;().For&lt;NHRepositoryTests&gt;() </code></pre> <p>...causes the fetching strategies registered against the NHRepositoryTests class to be used, and therefore the OrderItems and Products will be eager loaded without messing about with NHibernate mapping configurations.</p>
    singulars
    1. This table or related slice is empty.
    1. POHow To Implement The Query Side Of CQRS in DDD?
      singulars
      1. PTQuestion
    1. PTAnswer
    1. USCommunity
    1. USrohancragg
    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. COThis is a valid point. However It only really applies if you were to return your Entities to your Facade layer and then map to DTOs. My suggestion here would be to use the returned IQueryable and project directly into the DTOs. This way you avoid any FetchStrategies. You can even do projection at NHibernate mapping level as well.
      singulars
      1. PO
      1. USwillbt
    2. COOf course! Yes, thanks. I'm still coming to terms with how having NHibernate.Linq changes the game, but if you look at how Ritesh is embracing IQueryable you'll see he certinaly 'gets it' and is building good things around it (i.e. Specifications that take an Expression in their constructor).
      singulars
      1. PO
      1. USrohancragg
    3. COlinks now updated to GitHub locations
      singulars
      1. PO
      1. USrohancragg
 

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