I have a message table that self joins to itself where Message.ID == Message.Parent. So I have 1 Message with several ChildMessages. This is set up nicely with a Navigation property.
The code is currently:
var message = from m in soe.Messages.Include("ChildMessages")
where m.ID == id
&& m.IsActive
select m;
return message.FirstOrDefault();
What I really want is to only return 1 Message (that is equal to a particular ID and isActive) with all of its Active ChildMessages and I want to do it in one call to the database.
Is there a way to cap the number of records returned when an .Include() method is called on an ObjectQuery<>? Basically, if one of my entities is in a one-to-many relationship, such as a Band entity to a list of Fan entities (where a band can have any number of fans), how can I limit the number of fans returned?
In the example: var band = ctx.Bands.Include("Fans").SingleOrDefault(b => b.BandId == someBandId);
If I use the Include, it will return all fans. How can I query that Fans navigation property to return only a subset or max?
I have two tables with a foreign key constraint how can I delete rows from both of them in one transaction? linq to SQL seems to call my deletes in the wrong order. Is there somewhere I can check and make sure the constraint is recognized properly by linq to SQL??
How to use Stored Procedures with Linq to Entities? I prefer an example with input and output The videos on asp.net only show how to do this with Linq to SQL.
SELECT * FROM MessageAlerts AS A LEFT OUTER JOIN Contacts AS C ON A.ContactId = C.Id LEFT OUTER JOIN Users AS U ON A.UserId = U.Id INNER JOIN Businesses AS B ON B.Id = C.BusinessId OR B.UserId = U.Id
how to do this : ON B.Id = C.BusinessId OR B.UserId = U.Id with linq in entity framework.
WHY are all the examples on this site linq to SQL? Did ms not themselves announce dropping support for l2SQL over a year ago? i really don't get it. Examples are great.. but really not helping me since i've gone ahead and listened to MS. And can someone at MS clarify what the position is for linq 2 SQL.. Is it supported? Recommended? What the hell.
I am trying to learn LINQ to entities, and am working out how to best structure my BLL layer. I have generated the entity model and have created a generic repository in my DAL that returns results as IList<T>. I initially created the BLL to also return
results as IList<T>:
public IList<DAL.Customer> SelectAll() { [code]...
Now I am working on the aspx page, and I can create an ObjectDataSource and configure it to use my BLL, but since I am returning IList, I can't sort since I am not using a DataView. I have seen some articles on the web for converting IList to DataView, but that seems like a lot of overhead for every query.My goal is to keep a clean separation between layers without making things overly complicated. I would like to know how others have done this, or maybe a link to a good tutorial that shows how to structure all three layers.
I am building a web application in asp.Net 4.0 and entity framework. I am trying to retrieve a list of products based on a collection of id's. I first gather all the id's in a collection and then pass it to the linq query. I am trying to get a functionality similar to the IN clause in SQL. The problem seems to be with the Contains() method in the Linq to entities query. Here is my Linq code:
[Code]....
I got the above Linq to entities method from here: [URL]
i have a table with a field name called 'Firstname' and another field name called 'Lastname'. I would want to have a single column in my GridView which show Fullname and then the firstname and lastname are showed here under an alias. Also, i am binding my GridView using LINQ.So is there a way to create aliaswith LINQ and to use these with GridView ? Would love to have an hint about how i can realize this task.
I use the Entity Framework and Linq to Entities with MVC 2.0. When use the DropDownListFor from Html helpers to populate a dropdown that contains an ID from a foreign object, I post the form data but I canīt set the correct relation. Using the debug, I can see the ID retrieved from dropdown at my returned foreign object ID, but I think that I not use the association correctly.
have already used the latest technology in a professional manner. NETBasically I have two tables related 1 to 1:the Users table and the table ProfiloPersonale is the key to the Users table that this table are ProfiloPersonale iduser and type uniqueidentifier and diagram sql server 2008 I can clearly see the report, I also did a test to insert a record in the users table ( fictional) directly from sql server and everything works.With LINQ to Entities does not work:The entities 'LEntities.Users' part of the eport 'ProfiloPersonale'.Found 'ProfiloPersonale' related to 0.Expected 1 'ProfiloPersonale'Of course what I am doing is to first create the user and then create their profile in the db, taking the id of the registered
I have a view on my database and I am trying to add a new record using the AddTo method but it is not working. I noticed that LinqToEntities is creating the insert statement like this
Insert into (select field1, field2 from my_view) (field1, field2) values (value1, value2)
Is it possible to make LinqToEntities create the insert statement like the one below ?
Insert into my_view (field1, field2) values (value1, value2)
All I am trying to do is query the database, then get the returned values, so that I can do some calculations. But, I don't understand how to get the values from the database row that is returned, so that I can assign it for usage.
I would like to do something where the logic goes: for the index of [1] (which is just column 1), multiply it by 2. For the index of [2] (which is just column 2), multiply it by 3.
In the code bdehind && syntax does not work, any ideas?
Entities ctx3 = new Entities(); var uniqueQuote = from quot in ctx3.Quotes.Include("aspnet_Users").Include("Enquiries") where quot.Enquiries.EnquiryId == selectedEnquiryId && [code]...
Error 2 Delegate 'System.Func' does not take '1' arguments C:LocalGarageFinderLocalGarageFinderEnquiryDetail.aspx.cs 56 33 LocalGarageFinder
I am use the new ASP.NET MVC 2 and Entity Framework, but when I try to create a new view with strongly-typed option selected, the entity objects is not appears at dropdown and I cannot use the view creation wizard. I recompile the solution, but still not appears yet. Have any workaround that I forgot to do to enable the entities to be displayed at dropdownlist ?
I am working on a website similar to nerddinner. Is it possible to perform similar join using Linq to entities what is done with linq to sql in nerddinner.I am posting the codes below.
public IQueryable<Dinner> FindByLocation(float latitude, float longitude) { var dinners = from dinner in FindUpcomingDinners() join i in db.NearestDinners(latitude, longitude)
I have a solution which uses Linq to SQL Data Classes to acced the db. I have a project for my domain objects in my solution, which is a class library and has the dbml file. When I set up the dmbl using the wizard, Visual Studio created anapp.config file on that project with the connection string. It also creatting asettings file with the same info. I've noticed that if I change the connection string in the settings file, the app.config gets updated, which is the expected behaviour.
However, I'm having a problem when I deploy my web site to the production server. I already set the app.config file's Build Action to "Content", and also set Copy to ouput directory to "Always". Nevertheless, when I install the web site and change the connection string in the app.config file, it still takes the old connection string, so obviously I get an error. I've found that it only works if I change it with in Visual Studio and then compile, but of course that's not an optimal solution, because any change in the production db server would mean I have to change my project's assembly, thus generating a new version.
What do I have to configure so that the assembly takes the connection string form my app.config file directly after I deploy?
I have the following LINQ query that does a left join:
var results = from v in ctx.dat_Visitor join sp in ctx.vwSP on v.lu_Mentor.ID equals sp.ID into sp2 select new {
[code]...
My problem is that this LINQ query times out on me. I even upped the default timeout from 15 seconds to 120 seconds and it still times out. dat_Visitor has no more than 10 records in it, but vwSP (which is a view) has somewhere around 100,000 records. I know for sure that the timeout has to do with when I attempt to actually return sp2 in the results. If I change my LINQ query to not return sp2 in the results, then it is quick. Without sp2 the query looks like such:
var results = from v in ctx.dat_Visitor join sp in ctx.vwSP on v.lu_Mentor.ID equals sp.ID into sp2 select new { Visitor = v.Name, Tot = sp2.Count() };
Lastly, I'm using the 3.5 framework, but I am having serious thoughts about upgrading the website to 4.0, since I could then use DefaultIfEmpty().
