I've the following:
using (ISession session = Config.SessionFactory.OpenSession())
{
using (ITransaction transaction = session.BeginTransaction())
{
// This is a System.Collections.ArrayList,contains all my records returned from the session
var list = session.CreateSQLQuery(selectQuery).List();
// I want to put these records in an ObservableCollection of a specific Type
// Something like htis:
MyCollection = new ObservableCollection<MyType>(list);
}
}
This is not working and casting isn't an option here. Is there any way to put my retrurned list to the ObservableCollection?
I've got my ObservableCollection filled by using the following:
var query = session.CreateSQLQuery(selectQuery).AddEntity(typeof(MyType));
myObservableCollection = new ObservableCollection<MyType>(query.List<MyType>());
The List() returns ArrayList. Each value in ArrayList has some value which is type of object.
It can not be converted into directly any specific class. so create a mapping file then only you can get list of your required object.
Related
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 have some properties in my viewmodel. At runtime I need to add one more property into that viewmodel.
For example:
var avm= new AnalysisViewModel();
foreach (var grades in gradeList)
{
avm = new AnalysisViewModel
{
InfractionAverage = searchResult.Where(x=>x.GradeId == grades),
//Here i want to add one move property and want to assign value for my list.
};
}
Please guide me how to achieve this requirement
Hmm try with PropertyBuilder. http://msdn.microsoft.com/en-us/library/system.reflection.emit.propertybuilder.aspx
I have an IEnumerable and I would like to do a batch insert (240,000+ records). I've been perusing the forums and SO and I haven't been able to come up with something that works...
The other catch is that I need to be able to specify a different provider, as these records need to be inserted into a database with a different connection string.
Basically, something like this:
IEnumerable<MyObject> records = GetRecords();
SubSonicDooHickey.BatchSave(records, "differentSubsonicProvider")
I know that isn't exact, but something along those lines...
I've tried:
var itemsToSaveCollection = new ItemCollection(); // Your collection type here
foreach (var xmlItem in xmlItems)
{
var item = new Item(); // Your data model type here
// Set item values from xml
itemsToSaveCollection.Add(item);
}
itemsToSaveCollection.BatchSave();
(and several others) but couldn't get them to work...the above code didn't work because I couldn't find an appropriate collection from subsonic that had a .BatchSave function on it, and I also wouldn't know how to change the provider.
Turns out I didn't need this, but I was able to get this to work using a command:
var sql = "insert into foo(col1) values('#Param1'),('#Param2')";
var cmd = new QueryCommand(sql, repositoryName);
cmd.AddParameter("#Param1", "value1", DbType.String);
cmd.AddParameter("#Param2", "value2", DbType.String);
DataService.ExecuteQuery(cmd)
I'm new to NHibernate and was assigned to a task where I have to change a value of an entity property and then compare if this new value (cached) is different from the actual value stored on the DB. However, every attempt to retrieve this value from the DB resulted in the cached value. As I said, I'm new to NHibernate, maybe this is something easy to do and obviously could be done with plain ADO.NET, but the client demands that we use NHibernate for every access to the DB. In order to make things clearer, those were my "successful" attempts (ie, no errors):
1
DetachedCriteria criteria = DetachedCriteria.For<User>()
.SetProjection(Projections.Distinct(Projections.Property(UserField.JobLoad)))
.Add(Expression.Eq(UserField.Id, userid));
return GetByDetachedCriteria(criteria)[0].Id; //this is the value I want
2
var JobLoadId = DetachedCriteria.For<User>()
.SetProjection(Projections.Distinct(Projections.Property(UserField.JobLoad)))
.Add(Expression.Eq(UserField.Id, userid));
ICriteria criteria = JobLoadId.GetExecutableCriteria(NHibernateSession);
var ids = criteria.List();
return ((JobLoad)ids[0]).Id;
Hope I made myself clear, sometimes is hard to explain a problem when even you don't quite understand the underlying framework.
Edit: Of course, this is a method body.
Edit 2: I found out that it doesn't work properly for the method call is inside a transaction context. If I remove the transaction, it works fine, but I need it to be in this context.
I do that opening a new stateless session for geting the actual object in the database:
User databaseuser;
using (IStatelessSession session = SessionFactory.OpenStatelessSession())
{
databaseuser = db.get<User>("id");
}
//do your checks
Within a session, NHibernate will return the same object from its Level-1 Cache (aka Identity Map). If you need to see the current value in the database, you can open a new session and load the object in that session.
I would do it like this:
public class MyObject : Entity
{
private readonly string myField;
public string MyProperty
{
get { return myField; }
set
{
if (value != myField)
{
myField = value;
DoWhateverYouNeedToDoWhenItIsChanged();
}
}
}
}
googles nhforge
http://nhibernate.info/doc/howto/various/finding-dirty-properties-in-nhibernate.html
This may be able to help you.
How do I re-read some (class) Items from the database? I have read them once and made same updates, updates I dont wont to save. Now I need a complete fresh collection of Items from the database.
I have noticed that there are a function called SetForceCacheRefresh, but how do I use it with a CreateCriteria?
// Mats
IList<T> list = null;
using (Repository rep = new Repository())
{
IQuery iqry = rep.Session.CreateQuery(hql);
iqry.SetForceCacheRefresh(true);
list = iqry.List<T>();
}
Note: Before calling List(), set SetForceCacheRefresh(true) to refresh.