i have a database containing Song objects. The song class has > 30 properties.
My Music Tagging application is doing changes on a song on the file system.
It then does a lookup in the database using the filename.
Now i have a Song object, which i created in my Tagging application by reading the physical file and i have a Song object, which i have just retrieved from the database and which i want to update.
I thought i just could grab the ID from the database object, replace the database object with my local song object, set the saved id and store it.
But Raven claims that i am replacing the object with a different object.
Do i really need to copy every single property over, like this?
dbSong.Artist = songfromFilesystem.Artist;
dbSong.Album = songfromFileSystem.Album;
Or are there other possibilities.
thanks,
Helmut
Edit:
I was a bit too positive. The suggestion below works only in a test program.
When doing it in my original code i get following exception:
Attempted to associate a different object with id 'TrackDatas/3452'
This is produced by following code:
try
{
originalFileName = Util.EscapeDatabaseQuery(originalFileName);
// Lookup the track in the database
var dbTracks = _session.Advanced.DocumentQuery<TrackData, DefaultSearchIndex>().WhereEquals("Query", originalFileName).ToList();
if (dbTracks.Count > 0)
{
track.Id = dbTracks[0].Id;
_session.Store(track);
_session.SaveChanges();
}
}
catch (Exception ex)
{
log.Error("UpdateTrack: Error updating track in database {0}: {1}", ex.Message, ex.InnerException);
}
I am first looking up a song in the database and get a TrackData object in dbTracks.
The track object is also of type TrackData and i just put the ID from the object just retrieved and try to store it, which gives the above error.
I would think that the above message tells me that the objects are of different types, which they aren't.
The same error happens, if i use AutoMapper.
any idea?
You can do what you're trying: replace an existing object using just the ID. If it's not working, you might be doing something else wrong. (In which case, please show us your code.)
When it comes to updating existing objects in Raven, there are a few options:
Option 1: Just save the object using the same ID as an existing object:
var song = ... // load it from the file system or whatever
song.Id = "Songs/5"; // Set it to an existing song ID
DbSession.Store(song); // Overwrites the existing song
Option 2: Manually update the properties of the existing object.
var song = ...;
var existingSong = DbSession.Load<Song>("Songs/5");
existingSong.Artist = song.Artist;
existingSong.Album = song.Album;
Option 3: Dynamically update the existing object:
var song = ...;
var existingSong = DbSession.Load<Song>("Songs/5");
existingSong.CopyFrom(song);
Where you've got some code like this:
// Inside Song.cs
public virtual void CopyFrom(Song other)
{
var props = typeof(Song)
.GetProperties(System.Reflection.BindingFlags.Public | System.Reflection.BindingFlags.Instance)
.Where(p => p.CanWrite);
foreach (var prop in props)
{
var source = prop.GetValue(other);
prop.SetValue(this, source);
}
}
If you find yourself having to do this often, use a library like AutoMapper.
Automapper can automatically copy one object to another with a single line of code.
Now that you've posted some code, I see 2 things:
First, is there a reason you're using the Advanced.DocumentQuery syntax?
// This is advanced query syntax. Is there a reason you're using it?
var dbTracks = _session.Advanced.DocumentQuery<TrackData, DefaultSearchIndex>().WhereEquals("Query", originalFileName).ToList();
Here's how I'd write your code using standard LINQ syntax:
var escapedFileName = Util.EscapeDatabaseQuery(originalFileName);
// Find the ID of the existing track in the database.
var existingTrackId = _session.Query<TrackData, DefaultSearchIndex>()
.Where(t => t.Query == escapedFileName)
.Select(t => t.Id);
if (existingTrackId != null)
{
track.Id = existingTrackId;
_session.Store(track);
_session.SaveChanges();
}
Finally, #2: what is track? Was it loaded via session.Load or session.Query? If so, that's not going to work, and it's causing your problem. If track is loaded from the database, you'll need to create a new object and save that:
var escapedFileName = Util.EscapeDatabaseQuery(originalFileName);
// Find the ID of the existing track in the database.
var existingTrackId = _session.Query<TrackData, DefaultSearchIndex>()
.Where(t => t.Query == escapedFileName)
.Select(t => t.Id);
if (existingTrackId != null)
{
var newTrack = new Track(...);
newTrack.Id = existingTrackId;
_session.Store(newTrack);
_session.SaveChanges();
}
This means you already have a different object in the session with the same id. The fix for me was to use a new session.
I'm very new to breeze/knockout, but I'm 99% of the way to doing what I need to do. I'm using the Hot Towel template, and I'm successfully retrieving a list of items via breeze. The entity (ITBAL) is a database first Entity Framework entity. When I look at the JSON coming back in Fiddler, I see the correct data. The problem is that all of the properties of data.results are dependentobservables, and not the raw values themselves.
We have a custom grid control that is trying to display the data.results array. Because it is not expecting observables, it is simply displaying "function dependentobservable" instead of the value.
I tried to unwrap the object, but keep getting the circular reference error. I don't know why that is, since ITBAL isn't associated with anything.
The data as Fiddler reports it:
[{"$id":"1","$type":"WebUIHtml5HotTowel.Models.ITBAL, WebUIHtml5HotTowel","IBITNO":"A100 ","IBWHID":"1 ","IBITCL":"50","IBITSC":"3 ","IBSUSP":" ","IBVNNO":"100 ","IBPRLC":" ","IBSCLC":" ","IBCCCD":"P","IBPICD":" ","IBSAFL":"Y","IBSTCS":399.99000,"IBUSCS":0.00000,"IBAVCS":414.95214,"IBLCST":7.00000,"IBLCCC":20.0,"IBLCDT":110923.0,"IBLSCC":20.0,"IBLSDT":130111.0,"IBLXCC":19.0,"IBLXDT":990102.0,"IBMXO1":2100.000,"IBMXO2":0.000,"IBMXO3":0.000,"IBMNO1":5.000,"IBMNO2":0.000,"IBMNO3":0.000,"IBFOQ1":0.000,"IBFOQ2":0.000,"IBFOQ3":0.000,"IBOHQ1":327.000,"IBOHQ2":0.000,"IBOHQ3":0.000,"IBAQT1":1576.000,"IBAQT2":0.000,"IBAQT3":0.000,"IBBOQ1":50.000,"IBBOQ2":0.000,"IBBOQ3":0.000,"IBPOQ1":448.000,"IBPOQ2":0.000,"IBPOQ3":0.000,"IBIQT1":1446.000,"IBIQT2":0.000,"IBIQT3":0.000,"IBRMD1":10.000,"IBRMD2":0.000,"IBRMD3":0.000,"IBRYD1":10.000,"IBRYD2":0.000,"IBRYD3":0.000,"IBISM1":0.000,"IBISM2":0.000,"IBISM3":0.000,"IBISY1":0.000,"IBISY2":0.000,"IBISY3":0.000,"IBAMD1":0.000,"IBAMD2":0.000,"IBAMD3":0.000,"IBAYD1":0.000,"IBAYD2":0.000,"IBAYD3":0.000,"IBMMD1":0.000,"IBMMD2":0.000,"IBMMD3":0.000,"IBMYD1":0.000,"IBMYD2":0.000,"IBMYD3":0.000,"IBSMD1":1.0,"IBSMD2":0.0,"IBSMD3":0.0,"IBSYD1":1.0,"IBSYD2":0.0,"IBSYD3":0.0,"IBBLME":335.000,"IBBLYO":2680.000,"IBBLLY":1441.000,"IBNMTY":8.0,"IBNMLY":11.0,"IBQSMD":21.000,"IBQSYD":21.000,"IBQSLY":20.000,"IBISMD":16318.19,"IBISYD":16318.19,"IBISLY":45714.87,"IBCSMD":373.46,"IBCSYD":373.46,"IBCSLY":67.00,"IBDQMD":0.000,"IBDQYD":0.000,"IBDQLY":0.000,"IBDSMD":0.00,"IBDSYD":0.00,"IBDSLY":0.00,"IBDCMD":0.00,"IBDCYD":0.00,"IBDCLY":0.00,"IBNOMD":18.0,"IBNOYD":18.0,"IBNOLY":18.0,"IBPKMD":15.0,"IBPKYD":15.0,"IBPKLY":14.0,"IBINUS":" ","IBIAID":0.0,"IBSAID":0.0,"IBCQT1":1527.000,"IBCQT2":0.000,"IBCQT3":0.000,"IBFCST":"Y","IBDRSH":" ","IBWMIU":"JP","IBFL15":" ","IBUS20":" ","IBLPR1":0.00000,"IBLPR2":0.00000,"IBLPR3":0.00000,"IBLPR4":0.00000,"IBLPR5":0.00000,"IBLPCD":" ","IBABCC":"B","IBPRCL":0.0,"IBQBCL":" ","IBACDC":"Y","IBTDCD":" ","IBDOUM":" ","IBTP01":0.0,"IBTP02":0.0,"IBTP03":0.0,"IBTP04":0.0,"IBLMCC":20.0,"IBLMDT":130513.0,"IBTMPH":"Y","IBCOMC":" ","IBCOMF":0.00000,"IBITCT":" ","IBEOQT":0.000,"IBITCM":0.0,"IBBRVW":" ","IBPTID":" ","IBQTLT":0.0000,"IBCTY1":"AUS","IBCTY2":"AUS","IBTXCD":"1","IBREVS":"Y","IBITXC":" ","IBMNOQ":0.000,"IBSTUS":0.000,"IBUS30":" ","IBPSLN":" ","IBPLIN":"N","IBUPDP":"Y","IBDFII":"2011-08-11T00:00:00.000","IBLHRK":"A","IBPLNC":" "}]
My Controller:
[BreezeController]
public class ItemInquiryController : ApiController
{
readonly EFContextProvider<AplusEntities> _contextProvider = new EFContextProvider<AplusEntities>();
[System.Web.Http.HttpGet]
public string Metadata()
{
return _contextProvider.Metadata();
}
[HttpGet]
public IQueryable<ITBAL> ItemBalances(string itemNumber, string warehouse)
{
return _contextProvider.Context.ITBALs.Where(i => i.IBITNO == itemNumber && i.IBWHID == warehouse)
.OrderBy(i => i.IBWHID)
.ThenBy(i => i.IBITNO);
}
}
The relevant portion from the viewmodel:
var manager = new breeze.EntityManager("api/ItemInquiry");
var store = manager.metadataStore;
var itbalInitializer = function (itbal) {
itbal.CompositeKey = ko.computed(function () {
return itbal.IBITNO() + itbal.IBWHID();
});
};
store.registerEntityTypeCtor("ITBAL", null, itbalInitializer);
var index = "0" + (args.pageNum * args.pageSize);
var query = new breeze.EntityQuery("ItemBalances")
.withParameters({ itemNumber: "A100", warehouse: "1" })
.take(args.pageSize);
if (index > 0) {
query = query.skip(index);
}
manager.executeQuery(query).then(function (data) {
vm.itbals.removeAll();
var itbals = data.results;//[0].Data;
itbals.forEach(function (itbal) {
vm.itbals.push(itbal);
});
vm.totalRecords(1);
itemBalancesGrid.mergeData(vm.itbals(), args.pageNum, parseInt(vm.totalRecords()));
}).fail(function (e) {
logger.log(e, null, loggerSource, true, 'error');
});
I figure I must be missing something fairly simple, but it is escaping me.
UPDATE: I removed the BreezeController attribute from the ApiController, and it works correctly.
Jon, removing the [Breeze] attribute effectively disables breeze for your application so I don't think that is the long term answer to your problem.
If you don't actually want entities for this scenario - you just want data - than a Breeze projection that mentions just the data to display in the grid would seem to be the best choice. Projections return raw data that are not wrapped in KO observables and are not held in the Breeze EntityManager cache.
If you want the data as cached entities and you also want to display them in a grid that doesn't like KO observable properties ... read on.
You can unwrap a KO'd object with ko.toJS. However, the grid is likely to complain about circular references (or throw an "out of memory" exception as some grids do) ... even if the entity has no circular navigation paths. The difficulty stems from the fact that every Breeze entity has an inherent circularity by way of its entityAspect property:
something.entityAspect.entity //'entity' points back to 'something'
Because you are using Knockout for your model library and because you say ITBAL has no navigation properties ("is not related to anything"), I think the following will work for you:
manager.executeQuery(query).then(success) ...
function success(data) {
var unwrapped = ko.toJS(data.results).map(
function(entity) {
delete entity.entityAspect;
return entity;
});
vm.itbals(unwrapped);
vm.totalRecords(1); // huh? What is that "parseInt ..." stuff?
itemBalancesGrid.mergeData(vm.itbals(), args.pageNum, parseInt(vm.totalRecords()));
})
ko.toJS is a Knockout function that recursively unwraps an object or collection of objects, returning copies of values. Then we iterate over the copied object graphs, deleting their entityAspect properties. The array of results is stuffed into the vm.itbals observable and handed along.
You can imagine how to generalize this to remove anything that is giving you trouble.
Extra
What the heck is vm.totalRecords? I sense that this is supposed to be the total number of matching records before paging. You can get that from Breeze by adding .inlineCount() to the breeze query definition. You get the value after the query returns from the data.inlineCount property.
Do you really need vm.itbals()? If all you do here is pass values to the grid, why not do that and cut out the middle man?
The following success callback combines these thoughts
function success(data) {
var unwrapped = ko.toJS(data.results).map(
function(entity) {
delete entity.entityAspect;
return entity;
});
itemBalancesGrid.mergeData(unwrapped, args.pageNum, data.inlineCount);
})