Ayende @ Rahien

Hi!
My name is Oren Eini
Founder of Hibernating Rhinos LTD and RavenDB.
You can reach me by phone or email:

ayende@ayende.com

+972 52-548-6969

, @ Q c

Posts: 5,953 | Comments: 44,410

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Porting MVC Music Store to RavenAdvanced Migrations


I noticed that I had  typo when I inserted the albums data, the artist data was stored as “Arist”. This give me a chance to show you how we can do a migration that is a bit more advanced.

using (var documentStore = new DocumentStore { Url = "http://localhost:8080" })
{
    documentStore.Initialise();

    var count = 0;

    do
    {
        var queryResult = documentStore.DatabaseCommands.Query("Raven/DocumentsByEntityName", new IndexQuery
        {
            Query = "Tag:`Albums`",
            PageSize = 128,
            Start = count
        });


        if (queryResult.Results.Length == 0)
            break;

        count += queryResult.Results.Length;
        var cmds = new List<ICommandData>();
        foreach (var result in queryResult.Results)
        {
            var arist = result.Value<JObject>("Arist");
            if(arist == null)
                continue;
                        
            result["Artist"] = arist;
            result.Remove("Arist");

            cmds.Add(new PutCommandData
            {
                Document = result,
                Metadata = result.Value<JObject>("@metadata"),
                Key = result.Value<JObject>("@metadata").Value<string>("@id"),
            });
        }

        documentStore.DatabaseCommands.Batch(cmds.ToArray());

    } while (true);
    
}

The code itself should be hard to follow I think, it shows how we can manipulate documents by working with the JSON document directly, instead of having to go through an object layer.

More posts in "Porting MVC Music Store to Raven" series:

  1. (31 May 2010) StoreManagerController, part 2
  2. (29 May 2010) StoreManagerController
  3. (28 May 2010) Porting the checkout process
  4. (25 May 2010) StoreController
  5. (24 May 2010) Advanced Migrations
  6. (23 May 2010) Migrations
  7. (22 May 2010) Porting the HomeController, the Right Way
  8. (21 May 2010) Porting the HomeController, the map/reduce way
  9. (20 May 2010) Data migration
  10. (19 May 2010) Setting up the application
  11. (18 May 2010) The data model

Comments

NC
NC

"The code itself should be hard to follow"

Should or Shouldn't?

Code makes sense.

Frank Quednau

I think it isn't very hard to follow, if you want it to, you should try a bit harder. This is the second time you're using a "while true...do" pattern. Is this because of the asynchronous nature of setting up the index? If that's the case, it could be helpful to have some high-level construct for situations like that that blocks until the desired effect is in place.

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