I was wondering if someone could give me some input on my repository code and make any suggestions on how I might improve the code? Below I will include the repository class and the controller. Also, if I wanted to insert a value at the top of the list, what is a nice way to do that?
public static List<ChartApp> ListApplications()
{
using (var db = new LatencyDBContext())
{
var appNames = db.LoginApplications.Select(item => new ChartApp()
{
LoginApplicationID = item.LoginApplicationID,
LoginAppName = item.LoginAppName,
});
return appNames.ToList();
}
}
And, the controller:
var listApps = LoginApplicationRepository.ListApplications().OrderBy(item => item.LoginAppName);
var myCharts = new ChartsViewModel();
myCharts.AppsForChart = listApps.ToList();
Firstly the structure of the code looks fine to me, the OrderBy could be done in the repository - especially if the listing should normally be ordered by LoginAppName. There isn't a need to call ToList() on listApps in the controller as this has already been done in the repository so listApps is already a list.
To insert an item at the start of the list use the Insert method, eg:
listApps.Insert(0, newAppItem);
Related
I want to find any entity that inherits from DbEntity and has the field DeletedDate set to a value older than 100 days.
I have managed to piece together this code. But I am unsure of how I can go from this to querying the database for relevant entities.
var softDeletableEntities = _applicationContext.Model.GetEntityTypes()
.Where(e =>
typeof(DbEntity).IsAssignableFrom(e.ClrType)
&& e.BaseType == null
);
foreach (var entity in softDeletableEntities)
{
var entry = _applicationContext.Entry(entity.ClrType);
entry.Property<DateTimeOffset?>("DeletedDate");
// how do I find any Entity where (DeletedDate != null) and delete it?
}
I was hoping to be able to do something like this, but Set<> can't be used like that:
// Not ok to use Set<>() as below. Gives: 'entity' is a variable but is used like a type
var dataSet = _applicationContext.Set<entity.ClrType>();
var deleteOlderThan = DateTime.Now.AddDays(-100);
var toDelete = dataSet.Where(x => x.DeletedDate < deleteOlderThan);
dataSet.RemoveRange(toDelete);
_applicationContext.SaveChanges();
Any tips :)?
I would suggest to use EF Core extension linq2db.EntityFrameworkCore, note that I'm one of the creators. Install appropriate version 5.x for EF Core 5, 6.x for EF Core 6, etc.
Then you can execute the following query:
var dataSet = _applicationContext.Set<entity.ClrType>();
var deleteOlderThan = DateTime.Now.AddDays(-100);
var toDelete = dataSet.Where(x => x.DeletedDate < deleteOlderThan);
toDelete.Delete(); // method from Extension
Our current system is using Lazyloading by default (it is something I am going to be disabling but it can't be done right now)
For this basic query I want to return two tables, CustomerNote and Note.
This is my query
using (var newContext = new Entities(true))
{
newContext.Configuration.LazyLoadingEnabled = false;
var result = from customerNotes in newContext.CustomerNotes.Include(d=>d.Note)
join note in newContext.Notes
on customerNotes.NoteId equals note.Id
where customerNotes.CustomerId == customerId
select customerNotes;
return result.ToList();
}
My result however only contains the data in the CustomerNote table
The linked entities Customer and Note are both null, what am I doing wrong here?
I got it working with the following which is much simpler than what I've found elsewhere
Context.Configuration.LazyLoadingEnabled = false;
var result = Context.CustomerNotes.Where<CustomerNote>(d => d.CustomerId == customerId)
.Include(d=>d.Note)
.Include(d=>d.Note.User);
return result.ToList();
This returns my CustomerNote table, related Notes and related Users from the Notes.
That is callled eager loading you want to achieve.
var customerNotes = newContext.CustomerNotes.Include(t=> t.Node).ToList();
This should work, i don't really understand the keyword syntax.
If the code above doesn't work try this:
var customerNotes = newContext.CustomerNotes.Include(t=> t.Node).Select(t=> new {
Node = t.Node,
Item = t
}).ToList();
I have an object with several really large string properties. In addition, it has a simple timestamp property.
What I trying to achieve is to update only timestamp property without getting the whole huge object to the server.
Eventually, I would like to use EF and to do in the most performant way something equivalent to this:
update [...]
set [...] = [...]
where [...]
Using the following, you can update a single column:
var yourEntity = new YourEntity() { Id = id, DateProp = dateTime };
using (var db = new MyEfContextName())
{
db.YourEntities.Attach(yourEntity);
db.Entry(yourEntity).Property(x => x.DateProp).IsModified = true;
db.SaveChanges();
}
OK, I managed to handle this. The solution is the same as proposed by Seany84, with the only addition of disabling validation, in order to overcome issue with required fields. Basically, I had to add the following line just before 'SaveChanges():
db.Configuration.ValidateOnSaveEnabled = false;
So, the complete solution is:
var yourEntity = new YourEntity() { Id = id, DateProp = dateTime };
using (var db = new MyEfContextName())
{
db.YourEntities.Attach(yourEntity);
db.Entry(yourEntity).Property(x => x.DateProp).IsModified = true;
db.Configuration.ValidateOnSaveEnabled = false;
db.SaveChanges();
}
Im building a search function for an application with Lucene.NET and NHibernate.Search. To index the existing data I am using this method:
public void SynchronizeIndexForAllUsers()
{
var fullTextSession = Search.CreateFullTextSession(m_session);
var users = GetAll();
foreach (var user in users)
{
if (!user.IsDeleted)
{
fullTextSession.Index(user);
}
}
}
Where I have marked the fields I want to index with following attribute:
[Field(Index.Tokenized, Store = Store.Yes, Analyzer = typeof(StandardAnalyzer))]
public virtual string FirstName
{
get { return m_firstName; }
set { m_firstName = value; }
}
But when I then inspect the indicies in Luke the fields still have uppercases, commas etc. which should have been removed by the StandardAnalyzer.
Does anyone have know what I am doing wrong?
I had similiar problem to yours, but I've been trying to use WhitespaceAnalyzer. Setting it in Field attribute didn't work for me either.
I've ended up setting it globally. I am using FluentNHibernate for configuration and it looks like that:
this._sessionFactory =
Fluently.Configure()
.Database(MsSqlConfiguration.MsSql2005
.ConnectionString(cs => cs
// cut
.ShowSql()
)
.Mappings(m => m.FluentMappings
// cut
)
.ExposeConfiguration(cfg =>
{
// important part: lucene.net and nhibernate.search
cfg.SetProperty("hibernate.search.default.directory_provider", typeof(NHibernate.Search.Store.FSDirectoryProvider).AssemblyQualifiedName);
cfg.SetProperty("hibernate.search.default.indexBase", #"~\Lucene");
cfg.SetProperty("hibernate.search.indexing_strategy", "event");
cfg.SetProperty(NHibernate.Search.Environment.AnalyzerClass, typeof(WhitespaceAnalyzer).AssemblyQualifiedName);
cfg.SetListener(NHibernate.Event.ListenerType.PostUpdate, new FullTextIndexEventListener());
cfg.SetListener(NHibernate.Event.ListenerType.PostInsert, new FullTextIndexEventListener());
cfg.SetListener(NHibernate.Event.ListenerType.PostDelete, new FullTextIndexCollectionEventListener());
})
.BuildSessionFactory();
Take a look at NHibernate.Search.Environment.AnalyzerClass. Funny thing is that it won't work for generic fulltext queries (i think that Lucene will use StandardAnalyzer), but that's another story :).
Hope this helps.
Ok, I must be working too hard because I can't get my head around what it takes to use the Entity Framework correctly.
Here is what I am trying to do:
I have two tables: HeaderTable and DetailTable. The DetailTable will have 1 to Many records for each row in HeaderTable. In my EDM I set up a Relationship between these two tables to reflect this.
Since there is now a relationship setup between these tables, I thought that by quering all the records in HeaderTable, I would be able to access the DetailTable collection created by the EDM (I can see the property when quering, but it's null).
Here is my query (this is a Silverlight app, so I am using the DomainContext on the client):
// myContext is instatiated with class scope
EntityQuery<Project> query = _myContext.GetHeadersQuery();
_myContext.Load<Project>(query);
Since these calls are asynchronous, I check the values after the callback has completed. When checking the value of _myContext.HeaderTable I have all the rows expected. However, the DetailsTable property within _myContext.HeaderTable is empty.
foreach (var h in _myContext.HeaderTable) // Has records
{
foreach (var d in h.DetailTable) // No records
{
string test = d.Description;
}
I'm assuming my query to return all HeaderTable objects needs to be modified to somehow return all the HeaderDetail collectoins for each HeaderTable row. I just don't understand how this non-logical modeling stuff works yet.
What am I doing wrong? Any help is greatly appriciated. If you need more information, just let me know. I will be happy to provide anything you need.
Thanks,
-Scott
What you're probably missing is the Include(), which I think is out of scope of the code you provided.
Check out this cool video; it explained everything about EDM and Linq-to-Entities to me:
http://msdn.microsoft.com/en-us/data/ff628210.aspx
In case you can't view video now, check out this piece of code I have based on those videos (sorry it's not in Silverlight, but it's the same basic idea, I hope).
The retrieval:
public List<Story> GetAllStories()
{
return context.Stories.Include("User").Include("StoryComments").Where(s => s.HostID == CurrentHost.ID).ToList();
}
Loading the the data:
private void LoadAllStories()
{
lvwStories.DataSource = TEContext.GetAllStories();
lvwStories.DataBind();
}
Using the data:
protected void lvwStories_ItemDataBound(object sender, ListViewItemEventArgs e)
{
if (e.Item.ItemType == ListViewItemType.DataItem)
{
Story story = e.Item.DataItem as Story;
// blah blah blah....
hlStory.Text = story.Title;
hlStory.NavigateUrl = "StoryView.aspx?id=" + story.ID;
lblStoryCommentCount.Text = "(" + story.StoryComments.Count.ToString() + " comment" + (story.StoryComments.Count > 1 ? "s" : "") + ")";
lblStoryBody.Text = story.Body;
lblStoryUser.Text = story.User.Username;
lblStoryDTS.Text = story.AddedDTS.ToShortTimeString();
}
}