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Bulk Update in Entity Framework Core

I pull a bunch of timesheet entries out of the database and use them to create an invoice. Once I save the invoice and have an Id I want to update the timesheet entries with the invoice Id. Is there a way to bulk update the entities without loading them one at a time?
void SaveInvoice(Invoice invoice, int[] timeEntryIds) {
context.Invoices.Add(invoice);
context.SaveChanges();
// Is there anything like?
context.TimeEntries
.Where(te => timeEntryIds.Contains(te.Id))
.Update(te => te.InvoiceId = invoice.Id);
}

Disclaimer: I'm the owner of the project Entity Framework Plus
Our library has a Batch Update feature which I believe is what you are looking for
This feature supports EF Core
// Is there anything like? YES!!!
context.TimeEntries
.Where(te => timeEntryIds.Contains(te.Id))
.Update(te => new TimeEntry() { InvoiceId = invoice.Id });
Wiki: EF Batch Update
EDIT: Answer comment
does it supports contains as in your example? I think this is coming from EF Core which is not supported feature in 3.1 version even
EF Core 3.x support contains: https://dotnetfiddle.net/DAdIO2
EDIT: Answer comment
this is great but this requires to have zero parameter public constructors for classes. which is not a great. Any way to get around this issue?
Anonymous type is supported starting from EF Core 3.x
context.TimeEntries
.Where(te => timeEntryIds.Contains(te.Id))
.Update(te => new { InvoiceId = invoice.Id });
Online example: https://dotnetfiddle.net/MAnPvw

As of EFCore 7.0 you will see the built-in BulkUpdate() and BulkDelete methods:
context.Customers.Where(...).ExecuteDelete();
context.Customers.Where(...).ExecuteUpdate(c => new Customer { Age = c.Age + 1 });
context.Customers.Where(...).ExecuteUpdate(c => new { Age = c.Age + 1 });
context.Customers.Where(...).ExecuteUpdate(c => c.SetProperty(b => b.Age, b => b.Age + 1));

Are you after the performance of simplified syntax?
I would suggest to use direct SQL query,
string query = "Update TimeEntries Set InvoiceId = <invoiceId> Where Id in (comma separated ids)";
context.Database.ExecuteSqlCommandAsync(query);
For comma separated ids you can do string.Join(',', timeEntryIds)
It depends on what you actually need. If you want to go with Linq, then you need to iterate through each object.

If TimeEntry has an association to Invoice (check the navigation properties), you can probably do something like this:
var timeEntries = context.TimeEntries.Where(t => timeEntryIds.Contains(te.Id)).ToArray();
foreach(var timeEntry in timeEntries)
invoice.TimeEntries.Add(timeEntry);
context.Invoices.Add(invoice);
//save the entire context and takes care of the ids
context.SaveChanges();

The IQueryable.ToQueryString method introduced in Entity Framework Core 5.0 may help with this scenario. This method will generate SQL that can be included in a raw SQL query to perform a bulk update of records identified by that query.
For example:
void SaveInvoice(Invoice invoice, int[] timeEntryIds) {
context.Invoices.Add(invoice);
context.SaveChanges();
var query = context.TimeEntries
.Where(te => timeEntryIds.Contains(te.Id))
.Select(te => te.Id);
var sql = $"UPDATE TimeEntries SET InvoiceId = {{0}} WHERE Id IN ({query.ToQueryString()})";
context.Database.ExecuteSqlRaw(sql, invoice.Id);
}
The major drawback of this approach is that you end up with raw SQL appearing in your code. However I don't know of any reasonable way to avoid that with current Entity Framework Core capabilities - you're stuck with this caveat, or the caveats of other answers posted here such as:
Introducing a dependency on another library such as Entity Framework Plus or ELinq.
Using DbContext.SaveChanges() which will involve the execution of multiple SQL queries to retrieve and update records one at a time rather than doing a bulk update.

In entity framework core , you can do with update range method. you can see some samples usage here .
using (var context = new YourContext())
{
context.UpdateRange(yourModifiedEntities);
// or the followings are also valid
//context.UpdateRange(yourModifiedEntity1, yourModifiedEntity2, yourModifiedEntity3);
//context.YourEntity.UpdateRange(yourModifiedEntities);
//context.YourEntity.UpdateRange(yourModifiedEntity1, yourModifiedEntity2,yourModifiedEntity3);
context.SaveChanges();
}

Bulk update supported with EF 7:
context
.TimeEntries
.Where(te => timeEntryIds.Contains(te.Id))
.ExecuteUpdate(s => s.SetProperty(
i => te.InvoiceId,
i => invoice.Id));
Also there is async version for this method ExecuteUpdateAsync.

in EF Core 7, use ExecuteUpdate(), what's new
var multipleRows = TableA.Where(t=>t.Id < 99);
multipleRows.ExecuteUpdate(t=>
t.SetProperty(
r => r.Salary,
r => r.Salary * 2));
//SQL already sent to database, do not run below
//SaveChanges();
SQL being generated by EF
UPDATE [t]
SET [t].[Salary] = [t].[Salary] * 2
FROM [TableA] AS [t]
WHERE [t].[ID] < 99

Entity Framework Takes Too Much Time where Adding "WHERE Clause"

I'm working on Schools System, and the System have many Users(teachers And Managers).
(Tools)
Asp.net 5 (MVC With C#) VS 2015
SQL SERVER (Azure)
Code-First Approach
Each user Assigned to One Or More Of Classes.
(The User Should only See His Classes And Students inside of Classes)
in the other side
to catch Each User Classes
I've write this Method
public static IEnumerable<Class> GetClasses()
{
string UserId = HttpContext.Current.User.Identity.GetUserId();
ApplicationDbContext db = new ApplicationDbContext();
var Job = db.Jobs.Where(j => j.UserId == UserId).FirstOrDefault();
if (Job.EntityLevelID == 1)
{
var x = db.Classes.Where(a => a.Levels.SupervisionCenter.Organization.Id == Job.EntityID) as IEnumerable<Class>;
return x;
}
return null;
}
in The Students List Controller I just want the User to get his Students which are Only in his Classes
to get all the Students i write this Code
var items = db.Students.AsEnumerable().Where(o => o.Name.ToLower().Contains(search)).AsQueryable();
This Code will Give all the Students, it takes around 10 Sec to load and finish all the data (But that's is not needed Bcs, i need to Filter on ClassID Field).
when i need to filter on user Permissions based-classes
I've edit the code to be
var items = db.Students.AsEnumerable().Where(o => o.Name.ToLower().Contains(search))
.Where(s => UserDB.GetClasses().Select(c => c.Id).Contains(s.ClassID.Value))
.AsQueryable();
in the Previous case, when i add the where query it takes more than 80 Sec
EDIT (1)
The Organization Chart Will Be
Organizations
SuperVisionCenter
Schools
Classes
So I don't know what is the Problem I've made it here, can you please advise me for this
Thanks And Regards.

The very first thing that is slowing you down is AsEnumerable()
See here the effects of using AsEnumerable()
Basically you are getting all students in memory then running your where clause in app memory instead of just getting selected students.
Edit 1:
o.Name.ToLower().Contains(search)
I dont think you need to do ToLower() as MSSQL is case insensitive by default. This should remove the need for db.Students.AsEnumerable()
Edit 2:
Why don't you use join ? That would be a good optimisation to begin with.
something like
List<Student> data = (from student in db.Students
join clss in db.Classes on student.Class equals clss
where student.Name.Contains(search)).ToList()

This solved My Problem, and it takes around 3 to 4 seconds only.
int[] Classes = UserDB.GetClasses().Select(c => c.Id).ToArray();
var items = db.Students.Where(o => o.Name.ToLower().Contains(search))
.Where(r => Classes.Contains(r.ClassID.Value)).AsQueryable();

LINQ: Is there a way to combine these queries into one?

I have a database that contains 3 tables:
Phones
PhoneListings
PhoneConditions
PhoneListings has a FK from the Phones table(PhoneID), and a FK from the Phone Conditions table(conditionID)
I am working on a function that adds a Phone Listing to the user's cart, and returns all of the necessary information for the user. The phone make and model are contained in the PHONES table, and the details about the Condition are contained in the PhoneConditions table.
Currently I am using 3 queries to obtain all the neccesary information. Is there a way to combine all of this into one query?
public ActionResult phoneAdd(int listingID, int qty)
{
ShoppingBasket myBasket = new ShoppingBasket();
string BasketID = myBasket.GetBasketID(this.HttpContext);
var PhoneListingQuery = (from x in myDB.phoneListings
where x.phonelistingID == listingID
select x).Single();
var PhoneCondition = myDB.phoneConditions
.Where(x => x.conditionID == PhoneListingQuery.phonelistingID).Single();
var PhoneDataQuery = (from ph in myDB.Phones
where ph.PhoneID == PhoneListingQuery.phonePageID
select ph).SingleOrDefault();
}

You could project the result into an anonymous class, or a Tuple, or even a custom shaped entity in a single line, however the overall database performance might not be any better:
var phoneObjects = myDB.phoneListings
.Where(pl => pl.phonelistingID == listingID)
.Select(pl => new
{
PhoneListingQuery = pl,
PhoneCondition = myDB.phoneConditions
.Single(pc => pc.conditionID == pl.phonelistingID),
PhoneDataQuery = myDB.Phones
.SingleOrDefault(ph => ph.PhoneID == pl.phonePageID)
})
.Single();
// Access phoneObjects.PhoneListingQuery / PhoneCondition / PhoneDataQuery as needed
There are also slightly more compact overloads of the LINQ Single and SingleOrDefault extensions which take a predicate as a parameter, which will help reduce the code slightly.
Edit
As an alternative to multiple retrievals from the ORM DbContext, or doing explicit manual Joins, if you set up navigation relationships between entities in your model via the navigable join keys (usually the Foreign Keys in the underlying tables), you can specify the depth of fetch with an eager load, using Include:
var phoneListingWithAssociations = myDB.phoneListings
.Include(pl => pl.PhoneConditions)
.Include(pl => pl.Phones)
.Single(pl => pl.phonelistingID == listingID);
Which will return the entity graph in phoneListingWithAssociations
(Assuming foreign keys PhoneListing.phonePageID => Phones.phoneId and
PhoneCondition.conditionID => PhoneListing.phonelistingID)

You should be able to pull it all in one query with join, I think.
But as pointed out you might not achieve alot of speed from this, as you are just picking the first match and then moving on, not really doing any inner comparisons.
If you know there exist atleast one data point in each table then you might aswell pull all at the same time. if not then waiting with the "sub queries" is nice as done by StuartLC.
var Phone = (from a in myDB.phoneListings
join b in myDB.phoneConditions on a.phonelistingID equals b.conditionID
join c in ph in myDB.Phones on a.phonePageID equals c.PhoneID
where
a.phonelistingID == listingID
select new {
Listing = a,
Condition = b,
Data = c
}).FirstOrDefault();
FirstOrDefault because single throws error if there exists more than one element.

How to execute query to select multiple attributes subject to several where clauses across two tables

I have two tables from which I want to select data from:
Document_Data
Document_info
I want to execute the following query :
SELECT DISTINCT Document_Data.DOC_CLASS, TITLE FROM Document_info,Document_Data WHERE (((DOC_STATUS = '1') AND (PORTAL = 'First Page'))) AND (Document_info.DOC_NUMBER = Document_Data.DOC_NUMBER AND Document_info.REVISION = Document_Data.REVISION AND STATUS = 'CURRENT' AND Document_Data.DOC_CLASS = 'MESSAGE')
Can anyone give me info on how to execute the following query using Linq?

I have made a few assumptions since your query did leave off a few table names. I assumed that STATUS was on the Document_data table and DOC_STATUS was on the Document_info table. If its any different, it shouldn't be hard to modify this query to work.
DbContext is your entity framework context or wherever your store your db collections.
dbContext.Document_info.Where(i => i.DOC_STATUS == "1" && i.PORTAL == "First Page")
.Join(dbContext.Document_data.Where(d => d.DOC_CLASS == "MESSAGE" && d.STATUS == "CURRENT"),
i => new { i.REVISION, i.DOC_NUMBER }, //Document_info
d => new { d.REVISION, d.DOC_NUMBER }, //Document_data
(i, d) => new { d.DOC_CLASS, i.TITLE }) //(Document_info, Document_data)
.Distinct()
.ToList();
The way this works is that it first filters the document_info table to what you wanted from there. It then joins it with a filtered Document_data table on a composite "key" made up of REVISION and DOC_NUMBER. After that, it runs the Distinct and executes the whole query with a ToList.
The above should compile to valid SQL (at least it would using the MySQL connector...I haven't tried anything like that with MSSQL, but I assume that since the MSSQL one works better than MySQL so it would make sense that it would work there too). This particular query would come out to be a little convoluted, however, and might not work very optimally unless you have some foreign keys defined on REVISION and DOC_NUMBER.
I would note that your query will only return things where d.DOC_CLASS == "MESSAGE" and so your results will be quite repetitious.

Inefficient entity framework queries

I have a following foreach statement:
foreach (var articleId in cleanArticlesIds)
{
var countArt = context.TrackingInformations.Where(x => x.ArticleId == articleId).Count();
articleDictionary.Add(articleId, countArt);
}
Database looks like this
TrackingInformation(Id, ArticleId --some stuff
Article(Id, --some stuff
what I want to do is to get all the article ids count from TrackingInformations Table.
For example:
ArticleId:1 Count:1
ArticleId:2 Count:8
ArticleId:3 Count:5
ArticleId:4 Count:0
so I can have a dictionary<articleId, count>
Context is the Entity Framework DbContext. The problem is that this solution works very slow (there are > 10k articles in db and they should rapidly grow)

Try next query to gather grouped data and them add missing information. You can try to skip Select clause, I don't know if EF can handle ToDictionary in good manner.
If you encounter Select n + 1 problem (huge amount of database requests), you can add ToList() step between Select and ToDictionary, so that all required information will be brought into memory.
This depends all your mapping configuration, environment, so in order to get good performance, you need to play a little bit with different queries. Main approach is to aggregate as much data as possible at database level with few queries.
var articleDictionary =
context.TrackingInformations.Where(trackInfo => cleanArticlesIds.Contains(trackInfo.ArticleId))
.GroupBy(trackInfo => trackInfo.ArticleId)
.Select(grp => new{grp.Key, Count = grp.Count()})
.ToDictionary(info => "ArticleId:" + info.Key,
info => info.Count);
foreach (var missingArticleId in cleanArticlesIds)
{
if(!articleDictionary.ContainsKey(missingArticleId))
articleDictionary.add(missingArticleId, 0);
}

If TrackingInformation is a navigatable property of Article, then you can do this:
var result=context.Article.Select(a=>new {a.id,Count=a.TrackingInformation.Count()});
Putting it into a dictionary is simple as well:
var result=context.Article
.Select(a=>new {a.id,Count=a.TrackingInformation.Count()})
.ToDictionary(a=>a.id,a=>a.Count);
If TrackingInforation isn't a navigatable property, then you can do:
var result=context.Article.GroupJoin(
context.TrackingInformation,
foo => foo.id,
bar => bar.id,
(x,y) => new { id = x.id, Count = y.Count() })
.ToDictionary(a=>a.id,a=>a.Count);