ADO.NET :: Entity Data Model - How To Use
Feb 16, 2011
I program in ASP.NET for a while now. My applications uses always the DataSet. Some told me that Entity Data Model is the DataSet for LINQ. Now I want to try to working with it I have some questions but can't find the answers. I hope someone can. When I build an application I use the 3-tier structure. So Presentation-layer, Business-layer and the Data-layer. Normally I had some classes in the Data layer with specific methods to interact with the DataSet. When I read the table or something I create an object for the business layer.
With the Entity Data Model it seems a little bit confusing. If I read a table (for example Company) the edmx has created an class already. So is the edmx a replacement for the Data-layer and also for the Business layer? Is the edmx also a good use for multi-user application or is a connected application better?
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Sep 29, 2010
getting data from multiple Entities models into an MVC controller. Most of the examples I have seen for using EF in an MVC2 app only use a single entitiy.
I have just started using MVC2 in C# using the Entity Framework models (CIOps.model) created from an SQL database. I can create the controller and views using single tables of the model in MVC2, but I just cannot get my head around how to get data from multiple entity tables into the controller (similar to joins in T-SQL). I have included an example below of the controller code that works with a single entity table, tbl_tours (tbl_tour in DB).
Could someone please illustrate how this code would be changed to include additional columns from FK tables in addition to tbl_tours columns. E.g. the clients name from the tbl_clients, the coordinators name from the tbl_employees, and costs from tbl_costs entities? Is it possible to do this directly using the EF model entities/classes that are already created and not use LINQ, POCO, Repositories, etc.? The FK relationships are already in the EF models. I have included the whole controller code, but I just need a few examples of how to join the multiple entities, not rewrite every CRUD function function in the controller. I think this will get me over the hump in using EF in an MVC2 App. Also ignore the fact I am using the home controller, this will change in the application.
[Code]....
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Mar 15, 2011
I am a newbie in mvc3 and i'm wondering how to use attribute like [Display(Name="")] for model that comes from an entity data model that I provide im my "Model" folder in my mvc3 project.
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Jan 10, 2011
I made a few changes to the DB in SQL server management studio then right clicked on the .edmx doc to get it to update. That seemed to work fine but when i compiled the app everything that referenced the EF seems to be broken.The Error list now contains the below error for all classes that used it.
The type or namespace name '' could not be found (are you missing a using directive or an assembly reference?)
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Nov 15, 2010
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Oct 25, 2010
Is there a way to export a EF 4.0 Data Model to EF 3.5?
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Oct 14, 2010
i have a database with 4 table aspnet_Users, Forum, Topic, Post thay are related:
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[Code]....
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Mar 8, 2011
when i create ado.net entity data model and I add two tables only one is added to entity data model
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Jan 30, 2011
I have followed this tutorial [URL] to get a google map displayed but now I want do the next step and read the long/lat and text out of my ADO.NET Entity Data Model and put it on the map (preferably the text should appear when clicking on the red spot in a white text box - as you know it from google). Has someone done this already and could let me know how I get the points on the google map? THis is how the function in my controller looks right now:
Function Map() As ActionResult
ViewData.Model = (From m In _db.ahn_mappoints Select m.LONG, m.LAT, BLOG = m.Text.Substring(0, 81) & "...").Take(2).ToList()
Return View()
End Function
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Oct 11, 2010
I've been using entity data models for quite a few sections of my website and find it really good for saving things to the database.
After searching for a while, I can't seem to find a good way to populate a new instance with data from a database other than using a data reader. E.G:
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Jun 9, 2010
We're upgrading our system core asp to asp.net mvc, but there is a problem with refreshing the Database Model, our system is a UDP listener Windows Service, and Instering data to our database, our web system reading the database and process it then render. Here is the problem, When i enter some data using DatabaseModel, there is no problem, but when Windows service insert records to database, i can see the record at the web, is there a way to refresh entity data model/
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May 17, 2010
How can I share the auto-generated entity data model (generated object classes) amongst all layers of my C# web app whilst only granting query access in the data layer? This uses the typical 3 layer approach: data, business, presentation.
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Aug 12, 2010
when i create my entity data model i have a situation in the DB like this :
TableFirst : [Id,IdTableSecond,IdTableSecondAgain];TableSecond[Id]
Created data model is: TableFirst.TableSecond and TableFirst.TableSecond1
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or they may change?
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Jun 7, 2010
I've described my model using an Ado Entity Data Model file (*.edmx), and i wish now to generate my db schema and tables from it. Is it possible?
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Jan 28, 2011
I am setting up my new project..We are using entity frame work 4.0..
Is there any way to generate all classes and interfaces as we create manually for 3-tier architecture...
Or do i need to generate manually...
Ex:
Itest.cs
Public Interface ITest
{
int testproperty {get;set:}
}
Test.cs
Public class Test: ITest
{
public int testproperty {get;set:}
}
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Apr 13, 2010
I have installed VS 2008. but i am not seeing .edmx file in asp.net template.
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Jul 10, 2010
I use ADO.net Entity Data model for work with database.
In my program, I want to update a record of user table, so I use the code below to do this.
In this function I send changed user info and then overwrite the information with the current user information.
After I run objUser = _user; and then call objContext.SaveChanges(); to save the changes.
But when I do this, the changes are not persisted to the database. I use this code for another programs but in this case the code does not work!
public void Update(tbLiUser _user)
{
LinkContext objContext = this.Context;
tbLiUser objUser = objContext.tbLiUsers.First(u => u.tluId == _user.tluId);
objContext.Attach(objUser);
objUser = _user;
objContext.SaveChanges();
}
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Oct 5, 2010
I'm using Entity data model to reflect my database and I generate Domain service from my Entity data model.I understand that if I have changes in my database, I can just choose "Update Model from Database", but there is no "Update Domain service from Model" option available.How should maintain my domain service? I'm not going to delete away it and regenerate it whenever there are some changes, right?
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Apr 6, 2010
my application have two tables. TableA and TableB TableA have one record
ID StudentName Age
1 MARK 20
I use selectlist to select StudentName .
ViewData["StudentName"] = new SelectList(_db.StudentSet.ToList(), "StudentName", "StudentName");
and then add to TableB. for this case , for me is success, but I also want to add the"Age" into TableB on same time. I don't know how to do it.
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Nov 1, 2010
I'm trying to customize correct displaying of dropdownlists so information shown in comboboxes is relevant to the kind of user logged on (maintaining referential integrity at data level)
e.g.: I have a user already logged on and depending on his profile I'd like to display to this user only the portion of the database that he would be allowed to see. That would mean that he might have acces to an specific subset of data, e.g.: businesstype = "3", loging level = "2", etc.
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Nov 22, 2010
How can i insert,update and delete records using entity framework data model.
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Jun 4, 2010
I am getting error while accessing entity model from web serviceSystem.NotSupportedException: SQL Server Compact is not intended for ASP.NET development. at System.Data.SqlServerCe.SqlCeRestriction.CheckExplicitWebHosting() at System.Data.SqlServerCe.SqlCeConnection..ctor() at System.Data.SqlServerCe.SqlCeProviderFactory.CreateConnection() at System.Data.EntityClient.EntityConnection.GetStoreConnection(DbProviderFactory factory) at System.Data.EntityClient.EntityConnection.ChangeConnectionString(String newConnectionString) at System.Data.EntityClient.EntityConnection..ctor(String connectionString) at System.Data.Objects.ObjectContext.CreateEntityConnection(String connectionString) at System.Data.Objects.ObjectContext..ctor(String connectionString, String defaultContainerName) at DataModel.LabTestDBEntities..ctor() in d:projects4.0 vs2010labtestlabtestsolutiondatamodeldbmodel.designer.cs:line 26 at DataService.Service1..ctor() in D:Projects4.0 VS2010LabTestLabTestSolutionDataServiceService1.asmx.cs:line 23
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Jun 16, 2010
MVCThe generated ADO.NET Entity Data Model loses ordinal positions of columns and reorders Entity Set column names alphabetically. This causes the columns in a new MVC VIEW to appear alphabetically and needs to be reordered by hand. I am using MySQL Database.
How can I retain the ordinal positions of columns?
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Jun 10, 2010
I've been using VS2010 to look at the new ASP.NET and specifically MVC 2. I have gone through the 0.8 release of the MvcMusicStore sample on CodeProject (good job so far).
Now, I'm working on a project to explore MVC more deeply and after creating a table in a local SQL table, I went to create an ADO.NET entity data model to work with the table data. When I get to the list of templates, the total list of templates are:
SQL Server Database Text File XML File XML Schema That's everything (meaning when C# is selected at the top of the dialog's installed templates).
I've re-installed VS2010 (gone through the control panel and the maintenance option for VS2010). There's no Linq, Data Set, Database Unit Test, nothing....
It was there before, it's not now.
UPDATE : I did find this article: [URL] I did run devenv /installvstemplates. It ran without errors, however, the error still persists.
The article said if the "solution" was not a real solution, to re-install VS2010 (Really???). So I went to do so. The ADO.NET entity object framework is installed.
Why would VS2010 "forget" something so intrinsic?
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Aug 19, 2010
When adding a stored procedure into the Entity Data Model I can select whether the procedure returns a scalar, a (new) complex type or one of the entity types I already defined.I mean assuming I have a view like this
CREATE VIEW FilteredFoos as SELECT Foo.* FROM Foo join ... WHERE ...(that is a view that implements some involved filtering, but returns all columns from one table) how do I add it to the project so that I can use the entity set, but get the Foo objects, not some new FilteredFoo objects.
var foos = myDB.FilteredFoos.Include("Bar").ToList();
foreach (Foo foo in foos) { ...
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