Entity Framework Tutorial - Knowledge Base (KB)
266 results for: in tag: linq-to-entities
Expression.Invoke in Entity Framework?
The Entity Framework does not support the ...Expression.Invoke... operator. You receive the following exception when trying to use it:..."The LINQ expression node type 'Invoke' is not supported in LINQ to Entities....Has anyone got a workaround for this ...
asked by Brad Leach
Performance of Linq to Entities vs ESQL
When using the Entity Framework, does ESQL perform better than Linq to Entities?...I'd prefer to use Linq to Entities (mainly because of the strong-type checking), but some of my other team members are citing performance as a reason to use ESQL. I would l...
asked by Brad Leach
How do I get the max ID with Linq to Entity?
I have a table User which has an identity column ...UserID..., now what is the correct Linq to Entity line of code that would return me the max ...UserID...?...I've tried:...using (MyDBEntities db = new MyDBEntities()) { var User = db.Users.Last(); ...
asked by Ray Fan
Optimize Group By in LINQ to Entities
I have this query in LINQ to Entities.... var query = (from s in db.ForumStatsSet where s.LogDate >= date1 && s.LogDate <= date2 group s by new { s.Topic.topicID, s.Topic.subject, s.Topic.Forum.forumName, s...
asked by Olaj
How do you do a SQL style 'IN' statement in LINQ to Entities (Entity Framework) if Contains isn't supported?
I'm using LINQ to Entities (not LINQ to SQL) and I'm having trouble creating an 'IN' style query. Here is my query at the moment:...var items = db.InventoryItem .Include("Kind") .Include("PropertyValues") ....
asked by JC Grubbs
'Contains()' workaround using Linq to Entities?
I'm trying to create a query which uses a list of ids in the where clause, using the Silverlight ADO.Net Data Services client api (and therefore Linq To Entities). Does anyone know of a workaround to Contains not being supported?...I want to do something ...
asked by James Bloomer
Linq to Entities / Entity Framework cross edmx "join"
I have two entities, each from a different database and therefore different edmx files. There is, however, an infered relationship between them....Foo... has many ...Bar...s for example....What's the easiest way to do this join in the EntityFramework, wit...
asked by NikolaiDante
Adding to the Where clause of an Update in LinQ-to-Entities
Let's say I have a table called Product, with three columns: Id, CustomerId, Name. Id is the primary key. The schema is outside of the control of my group, and we now have a requirement to always provide CustomerId as a parameter for all queries (selects...
asked by Joel Martinez
Which is the best book out there to learn Linq, including Linq to Entities?
I heard lots of reviews on the book Linq in Action, but it does not cover Linq to Entities. ... Please provide your feedback on the books you may have read.
asked by Binoj Antony
Error: The object cannot be deleted because it was not found in the ObjectStateManager
Trying to get a handle on Entity Framework here and I am hitting some speed bumps... I have a Get() method that works fine and has been tested, but my Delete method is not working:... public static void Delete(string name) { J1Entities db = ...
asked by naspinski
Is there a way to export the .edmx diagram from VS2008 to Visio?
Some people want to see the DB structure and dont have VS, is there a way to do this? Or any other way to export it outside of a screencapture (it is a huge diagram)....Thank you.
asked by naspinski
How do I delete an object from an Entity Framework model without first loading it?
I am quite sure I've seen the answer to this question somewhere, but as I couldn't find it with a couple of searches on SO or google, I ask it again anyway......In Entity Framework, the only way to delete a data object seems to be ...MyEntityModel ent = n...
asked by Tomas Aschan
How do you do full text search (FTS) with Linq to ADO.NET entity framework?
Now that SQL Server 2008 has full text search built in. I'm looking to use it to power my website's search. I'm also looking at using ADO.NET entity framework for my ORM but I was wondering how do you do full text search (FTS) with Linq to ADO.NET entity ...
asked by ajma
LINQ to Entities for subtracting 2 dates
I am trying to determine the number of days between 2 dates using LINQ with Entity Framework. It is telling me that it does not recognize Subtract on the System.TimeSpan class...Here is my where portion of the LINQ query....where ((DateTime.Now.Subtract(v...
asked by Michael I
How to create LINQ Expression Tree to select an anonymous type
I would like to generate the following select statement dynamically using expression trees:...var v = from c in Countries where c.City == "London" select new {c.Name, c.Population}; ...I have worked out how to generate...var v = from c in ...
asked by Tom Deloford
Linq to Entities, random order
How do i return matching entities in a random order?... Just to be clear this is Entity Framework stuff and LINQ to Entities....(air code)...IEnumerable<MyEntity> results = from en in context.MyEntity where en.type == myTyp...
asked by NikolaiDante
Why is Entity Framework taking 30 seconds to load records when the generated query only takes 1/2 of a second?
The executeTime below is 30 seconds the first time, and 25 seconds the next time I execute the same set of code. When watching in SQL Profiler, I immediately see a login, then it just sits there for about 30 seconds. Then as soon as the select statement...
asked by NotDan
Updating your edmx to reflect changes made in your db (.net linq-to-entities)
So I have my edmx made. ...Then I change my database a little bit, changing a column to from being a NOT NULL to allowing NULL....I go into my edmx, right click and choose "Update Model from Database"...Now I go into my program and it hasnt actually upda...
asked by Stuck In Baghdad
How can I attach an Entity Framework object that isn't from the database?
I have a complete separation of my Entity Framework objects and my POCO objects, I just translate them back and forth......i.e:...// poco public class Author { public Guid Id { get; set; } public string UserName { get; set; } } ...and then I have an...
asked by sontek
Entity Framework - Linq To Entities - Many-To-Many Query Problems
I am having problems querying many-to-many relationships in Linq To Entities. I am basically trying to replicate this query using Linq:...Select * FROM Customer LEFT JOIN CustomerInterest ON Customer.CustomerID = CustomerInterest.CustomerID LEFT JOIN In...
asked by JD.
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