This is in a WPF application.
Currently I have the following code which works, but is slow:
public void IgnoreOffers(ICollection<Offer> offers)
{
using (var context = new DbContext())
{
foreach (Offer o in offers)
{
var offer = context.Offers.Find(o.Id);
offer.Ignore = true;
}
context.SaveChanges();
}
}
I know all the offers exist already in the database
Is there a more performant way of doing this?
Disclaimer: I'm the owner of the project Entity Framework Plus
This library allows you to perform BatchUpdate
context.Offers.Where(o => offers.Contains(o.Id)
.BatchUpdate(o => new Offer() { Ignore = true });
If you have too many offers, you might need to do it in multiple batch as the number of parameter in SQL is limited.
Everything will be done on the database side, so no offer will be needed to be loaded on the application side.
This method will offer you the best performance.
Disclaimer: I'm the owner of the project Entity Framework Extensions
This library is not free but offers the BulkUpdate features.
// BulkUpdate
context.BulkUpdate(offers);
// If you want to only update the `Ignore` property
context.BulkUpdate(offers, o => o.ColumnInputExpression = x => new { x.Ignore });
Related
I'm developing a multitenant application and would like to have to option to remove a tenant. This however seems to be less trivial than one would assume.
My goal is to delete all references to the tenant everywhere in the database. I understand that Tenant is Soft-Delete, but I since I don't want my database to fill up with old meaningless data I've tried disabling the soft-delete filter.
Here is some code that I've tried:
using (_unitOfWorkManager.Current.DisableFilter(AbpDataFilters.SoftDelete))
{
await TenantRepository.DeleteAsync(x => x.Id == tenantId);
}
This did not work. The tenant is marked as "IsDeleted" but not removed.
Then I figured that maybe it has something to do with UnitOfWork so I made sure no UnitOfWork was active and then manually controlled it:
using (var unitOfWork = _unitOfWorkManager.Begin())
{
// the codeblock above went here
unitOfWork.Complete();
}
This did not work, same result. And this is just the AbpTenant table. I'm also trying to delete from all other tables. For example AbpSettings and AbpLanguages. It's very unclear to me how to do that at all - the "managers" doesn't contain any Delete functions.
I tried creating IRepository for these entities but it does not work. The error reads
The type Abo.Configuration.Setting cannot be used as a type parameter TEntity in the generic type or method IRepository. There is no implicit reference conversion from Abp.Configuration.Setting to Abo.Domain.Entities.IEntity.
That leaves me with the option to use the DataContext directly:
using (EntityFramework.MyDbContext db = new EntityFramework.MyDbContext())
{
List<PermissionSetting> perms = await db.Permissions.Where(x => x.TenantId == tenantId).ToListAsync();
for (int i=0; i<perms.Count(); i++)
{
db.Permissions.Remove(perms[i]);
}
// I also tried deleting them in bulk at first
// ((DbSet<PermissionSetting>)db.Permissions).RemoveRange(db.Permissions.Where(x => x.TenantId == tenantId));
await db.SaveChangesAsync();
}
I tried that with and without UnitOfWork.
But it simply does not get deleted from the database. I'm getting no errors or Exceptions.
Why does it not get deleted? How can I delete it? Surely it must be possible?
since I don't want my database to fill up with old meaningless data I've tried disabling the soft-delete filter.
From the question on Disable SoftDelete for AbpUserRole:
protected override void CancelDeletionForSoftDelete(EntityEntry entry)
{
if (IsSoftDeleteFilterEnabled)
{
base.CancelDeletionForSoftDelete(entry);
}
}
The type Abo.Configuration.Setting cannot be used as a type parameter TEntity in the generic type or method IRepository. There is no implicit reference conversion from Abp.Configuration.Setting to Abo.Domain.Entities.IEntity.
Inject IRepository<Setting, long> instead of IRepository<Setting>.
That leaves me with the option to use the DataContext directly
...
But it simply does not get deleted from the database. I'm getting no errors or Exceptions.
From the documentation on Data Filters:
using (_unitOfWorkManager.Current.DisableFilter(AbpDataFilters.MayHaveTenant))
{
using (var db = new ...)
{
// ...
}
}
That said, there is no way to easily delete related tenant data completely. Consider writing SQL.
I'm aware that there are some commercial libraries and that there's AddRange, but AFAIK AddRange does piecemeal INSERTs under the hood.
I'm looking for a free utility that I can use to add a collection of new entities all at the same time - does one exist for EF6?
I would suggest you take a look at N.EntityFramework.Extension. It is a basic bulk extension framework for EF 6 that is available on Nuget and the source code is available on Github under MIT license.
Install-Package N.EntityFramework.Extensions
https://www.nuget.org/packages/N.EntityFramework.Extensions
Once you install it you can simply use BulkInsert() method directly on the DbContext instance. It support BulkDelete, BulkInsert, BulkMerge and more.
BulkDelete()
var dbcontext = new MyDbContext();
var orders = dbcontext.Orders.Where(o => o.TotalPrice < 5.35M);
dbcontext.BulkDelete(orders);
BulkInsert()
var dbcontext = new MyDbContext();
var orders = new List<Order>();
for(int i=0; i<10000; i++)
{
orders.Add(new Order { OrderDate = DateTime.UtcNow, TotalPrice = 2.99 });
}
dbcontext.BulkInsert(orders);
You can use the following library:
https://github.com/MikaelEliasson/EntityFramework.Utilities
It works well for simple bulk inserts and updates.
You should also look at the following post if you want to find out about other options to achieve bulk insert:
Fastest Way of Inserting in Entity Framework
Say I open a .db4o file. What would be the Java code (psuedo) that would generate a list of unique Java CLASSES/TYPES contained in the database?
I am sure I could write the code to do it, but I am afraid it could be quite slow. Is there a good way to do this without querying for every object in the database? Could I use some sort of index?
I'd rather not rely on stored metadata about the database, I'd rather rely on the true information about what objects are actually stored within.
You can use something like (C# but it can be easily converted to Java :)
const string DatabaseFileName = "c:\\temp\\Learning.odb";
static void Main(string[] args)
{
using (var db = Db4oEmbedded.OpenFile(DatabaseFileName))
{
var classes = db.Ext().StoredClasses();
foreach (var #class in classes)
{
Console.WriteLine();
Console.WriteLine(#class.GetName());
foreach (var field in #class.GetStoredFields())
{
Console.WriteLine("\t{1} {0}", field.GetName(), field.GetStoredType().GetName());
}
}
}
}
Note that you have more interesting methods in ExtObjectContainer interface.
Hope this helps.
Background:
From another question here at SO I have a Winforms solution (Finance) with many projects (fixed projects for the solution).
Now one of my customers asked me to "upgrade" the solution and add projects/modules that will come from another Winforms solution (HR).
I really don't want to keep these projects as fixed projects on the existing finance solution. For that I'm trying to create plugins that will load GUI, business logic and the data layer all using MEF.
Question:
I have a context (DbContext built to implment the Generic Repository Pattern) with a list of external contexts (loaded using MEF - these contexts represent the contexts from each plugin, also with the Generic Repository Pattern).
Let's say I have this:
public class MainContext : DbContext
{
public List<IPluginContext> ExternalContexts { get; set; }
// other stuff here
}
and
public class PluginContext_A : DbContext, IPluginContext
{ /* Items from this context */ }
public class PluginContext_B : DbContext, IPluginContext
{ /* Items from this context */ }
and within the MainContext class, already loaded, I have both external contexts (from plugins).
With that in mind, let's say I have a transaction that will impact both the MainContext and the PluginContext_B.
How to perform update/insert/delete on both contexts within one transaction (unity of work)?
Using the IUnityOfWork I can set the SaveChanges() for the last item but as far as I know I must have a single context for it to work as a single transaction.
There's a way using the MSDTC (TransactionScope) but this approach is terrible and I'd reather not use this at all (also because I need to enable MSDTC on clients and server and I've had crashes and leaks all the time).
Update:
Systems are using SQL 2008 R2. Never bellow.
If it's possible to use TransactionScope in a way that won't scale to MSDTC it's fine, but I've never achieved that. All the time I've used TransactionScope it goes into MSDTC. According to another post on SO, there are some cases where TS will not go into MSDTC: check here. But I'd really prefer to go into some other way instead of TransactionScope...
If you are using multiple contexts each using separate connection and you want to save data to those context in single transaction you must use TransactionScope with distributed transaction (MSDTC).
Your linked question is not that case because in that scenario first connection do not modify data so it can be closed prior to starting the connection where data are modified. In your case data are concurrently modified on multiple connection which requires two-phase commit and MSDTC.
You can try to solve it with sharing single connection among multiple contexts but that can be quite tricky. I'm not sure how reliable the following sample is but you can give it a try:
using (var connection = new SqlConnection(connnectionString))
{
var c1 = new Context(connection);
var c2 = new Context(connection);
c1.MyEntities.Add(new MyEntity() { Name = "A" });
c2.MyEntities.Add(new MyEntity() { Name = "B" });
connection.Open();
using (var scope = new TransactionScope())
{
// This is necessary because DbContext doesnt't contain necessary methods
ObjectContext obj1 = ((IObjectContextAdapter)c1).ObjectContext;
obj1.SaveChanges(SaveOptions.DetectChangesBeforeSave);
ObjectContext obj2 = ((IObjectContextAdapter)c2).ObjectContext;
obj2.SaveChanges(SaveOptions.DetectChangesBeforeSave);
scope.Complete();
// Only after successful commit of both save operations we can accept changes
// otherwise in rollback caused by second context the changes from the first
// context will be already accepted = lost
obj1.AcceptAllChanges();
obj2.AcceptAllChanges();
}
}
Context constructor is defined as:
public Context(DbConnection connection) : base(connection,false) { }
The sample itself worked for me but it has multiple problems:
First usage of contexts must be done with closed connection. That is the reason why I'm adding entities prior to opening the connection.
I rather open connection manually outside of the transaction but perhaps it is not needed.
Both save changes successfully run and Transaction.Current has empty distributed transaction Id so it should be still local.
The saving is much more complicated and you must use ObjectContext because DbContext doesn't have all necessary methods.
It doesn't have to work in every scenario. Even MSDN claims this:
Promotion of a transaction to a DTC may occur when a connection is
closed and reopened within a single transaction. Because the Entity
Framework opens and closes the connection automatically, you should
consider manually opening and closing the connection to avoid
transaction promotion.
The problem with DbContext API is that it closes and reopens connection even if you open it manually so it is a opened question if API always correctly identifies if it runs in the context of transaction and do not close connection.
#Ladislav Mrnka
You were right from the start: I have to use MSDTC.
I've tried multiple things here including the sample code I've provided.
I've tested it many times with changed hare and there but it won't work. The error goes deep into how EF and DbContext works and for that to change I'd finally find myself with my very own ORM tool. It's not the case.
I've also talked to a friend (MVP) that know a lot about EF too.
We have tested some other things here but it won't work the way I want it to. I'll end up with multiple isolated transactions (I was trying to get them together with my sample code) and with this approach I don't have any way to enforce a full rollback automatically and I'll have to create a lot of generic/custom code to manually rollback changes and here comes another question: what if this sort of rollback fails (it's not a rollback, just an update)?
So, the only way we found here is to use the MSDTC and build some tools to help debug/test if DTC is enabled, if client/server firewalls are ok and all that stuff.
Thanks anyway.
=)
So, any chance this has changed by October 19th? All over the intertubes, people suggest the following code, and it doesn't work:
(_contextA as IObjectContextAdapter).ObjectContext.Connection.Open();
(_contextB as IObjectContextAdapter).ObjectContext.Connection.Open();
using (var transaction = new TransactionScope(TransactionScopeOption.Required, new TransactionOptions{IsolationLevel = IsolationLevel.ReadUncommitted, Timeout = TimeSpan.MaxValue}))
{
_contextA.SaveChanges();
_contextB.SaveChanges();
// Commit the transaction
transaction.Complete();
}
// Close open connections
(_contextA as IObjectContextAdapter).ObjectContext.Connection.Close();
(_contextB as IObjectContextAdapter).ObjectContext.Connection.Close();
This is a serious drag for implementing a single Unit of Work class across repositories. Any new way around this?
To avoid using MSDTC (distributed transaction):
This should force you to use one connection within the transaction as well as just one transaction. It should throw an exception otherwise.
Note: At least EF6 is required
class TransactionsExample
{
static void UsingExternalTransaction()
{
using (var conn = new SqlConnection("..."))
{
conn.Open();
using (var sqlTxn = conn.BeginTransaction(System.Data.IsolationLevel.Snapshot))
{
try
{
var sqlCommand = new SqlCommand();
sqlCommand.Connection = conn;
sqlCommand.Transaction = sqlTxn;
sqlCommand.CommandText =
#"UPDATE Blogs SET Rating = 5" +
" WHERE Name LIKE '%Entity Framework%'";
sqlCommand.ExecuteNonQuery();
using (var context =
new BloggingContext(conn, contextOwnsConnection: false))
{
context.Database.UseTransaction(sqlTxn);
var query = context.Posts.Where(p => p.Blog.Rating >= 5);
foreach (var post in query)
{
post.Title += "[Cool Blog]";
}
context.SaveChanges();
}
sqlTxn.Commit();
}
catch (Exception)
{
sqlTxn.Rollback();
}
}
}
}
}
Source:
http://msdn.microsoft.com/en-us/data/dn456843.aspx#existing
A multitenancy application is an app that is shared by multiple organizations (medical practices, law offices..) and each organization, in turn, has it's own users. They all log on a centralized environment.
To be identified within the application, the organization must be expressed in the URL. There are two major URL forms for that. Subdomains and folders:
[tenancy_name].appname.com/projects/view/123
www.appname.com/[tenancy_name]/projects/view/123
At first I tried the second because this solution does not involve dealing with DNSs. But then the problem: Everytime the developer needs to express an url (#Html.Action or #Url.Action) it has to explicitly pass the [tenancy_name]. This adds an unwanted overhead to the development. A possible workaround would be to implement custom versions of these HTML helpers that automatically take into account the tenancy name. I'm considering this option but looking for something more straitghtforward. I also realized ASP.NET MVC automatically passes route values for outgoing URLs but only when the controller and action are the same as the current. It would be nice if route values were always passed.
To implement the first option, the subdomain one, I think, I would need some third party DNS manager. I heard of DynDNS and took a look at it but I thought it unclear how they work just looking at their site. Would I need to trigger a web-service to tell them to create another subdomain everytime a new tenancy is created? Do they support wildcards in the DNS? Do they work on Windows Azure or shared hostings?
I'm here looking for directions. Which way should I go?
look this project on codeplex, the "baseRoute" maybe can help you.
http://mvccoderouting.codeplex.com/
Regards.
Following made View resolution trivial in our app:
How to use:
For views that you need to overload for a particular tenant - treat them same way as custom display modes:
Following will work:
Index.cshtml
Index.cust2.mobile.cshtml
or
Partials/CustomerAgreement.cust1.cshtml
Partials/CustomerAgreement.cust2.cshtml
as far as I remember display/editor templates also work same way
Known issues:
1. You have to create Layouts for all combinations of primary+secondary (for whatever MVC-reason)
2. Regardless of what resharper is saying about its support of display modes - it does not support "." as part of the display mode name (here's an issue to track progress http://youtrack.jetbrains.com/issue/RSRP-422413)
//put in application start --------
DisplayModeProvider.Instance.Modes.Clear();
foreach (var displayMode in GetDisplayModes())
{
DisplayModeProvider.Instance.Modes.Add(displayMode);
}
private IEnumerable<IDisplayMode> GetDisplayModes()
{
return new CompoundDisplayModeBuilder()
.AddPrimaryFilter(_ => dependencyResolver.GetService(typeof(IResolveCustomerFromUrl)).GetName(),
"cust1",
"cust2")
.AddSecondaryFilter(ctx => ctx.Request.Browser.IsMobileDevice, "mobile")
.BuildDisplayModes();
}
//end of application start part
//and the mode builder implementation:
public class CompoundDisplayModeBuilder
{
private readonly IList<DefaultDisplayMode> _primaryDisplayModes = new List<DefaultDisplayMode>();
private readonly IList<DefaultDisplayMode> _secondaryDisplayModes = new List<DefaultDisplayMode>();
//NOTE: this is just a helper method to make it easier to specify multiple tenants in 1 line in global asax
//You can as well remove it and add all tenants one by one, especially if resolution delegates are different
public CompoundDisplayModeBuilder AddPrimaryFilter(Func<HttpContextBase, string> contextEval, params string[] valuesAsSuffixes)
{
foreach (var suffix in valuesAsSuffixes)
{
var val = suffix;
AddPrimaryFilter(ctx => string.Equals(contextEval(ctx), val, StringComparison.InvariantCultureIgnoreCase), val);
}
return this;
}
public CompoundDisplayModeBuilder AddPrimaryFilter(Func<HttpContextBase, bool> contextCondition, string suffix)
{
_primaryDisplayModes.Add(new DefaultDisplayMode(suffix) { ContextCondition = contextCondition });
return this;
}
public CompoundDisplayModeBuilder AddSecondaryFilter(Func<HttpContextBase, bool> contextCondition, string suffix)
{
_secondaryDisplayModes.Add(new DefaultDisplayMode(suffix) { ContextCondition = contextCondition });
return this;
}
public IEnumerable<IDisplayMode> BuildDisplayModes()
{
foreach (var primaryMode in _primaryDisplayModes)
{
var primaryCondition = primaryMode.ContextCondition;
foreach (var secondaryMode in _secondaryDisplayModes)
{
var secondaryCondition = secondaryMode.ContextCondition;
yield return new DefaultDisplayMode(primaryMode.DisplayModeId + "." + secondaryMode.DisplayModeId){
ContextCondition = ctx => primaryCondition(ctx) && secondaryCondition(ctx)
};
}
}
foreach (var primaryFilter in _primaryDisplayModes)
{
yield return primaryFilter;
}
foreach (var secondaryFilter in _secondaryDisplayModes)
{
yield return secondaryFilter;
}
yield return new DefaultDisplayMode();
}
}