Is there a way to export a EF 4.0 Data Model to EF 3.5?
I looked around and found that we are not able to access EF 4.0 from a ASP.Net 3.5 project here: [URL]
Our project is the 1st to go to .Net 4.0 using Entity Framework and we (the team) were wondering if there was a way for the other projects that "might" need to access our data that are still using the .Net 3.5 framework.
How can i insert,update and delete records using entity framework data model.
View 1 RepliesI'm working on a new project where I have the luxury of working from a Model to Database approach using Entity Framework 4.
The project I'm working on is taking an agile approach where different phases will be rolled out over time.
Will the Model First approach work in my case? I noticed when you "Generate Database from Model" it recreates the entire schema from scratch which will obviously wipe all the data that is in the db. I was hoping for a more "Update Database from Model" approach where the db would just be altered to reflect the changes rather than recreated
There are some tutorials explaining how to create a Model based on Linq to Sql or The Ms Entity Framework. Can I use my custom code for a model? If we have the controller with the code :
[Code]....
This returns a List<Movie> to the view that knows what to do with it. Is it possible that I create a method called MovieSet that returns a List<Movie> using a sql qry or a stored procedure call without the creation of an Object for this purpose ? Or do I need a Movie object? Lets say that I just to do my query, loading data into a dataTable and load that data to a list of movie objects. Because the code created by the Entity Framerwork is too big for a quick reading.
I want to use entity framework model for visual studio 2010. I am using oracle database. i was wondering if it is possible to use entity framework for oracle. If it is not possible then I will just use simple ADO.net and call stord proc and packages. I already downloaded oracle data provider for entity frameowrk from codeplex web site. I could not see oracle database option when connecting to oracle databse in LINQ to sql. can someone give me any example that connects to a sample oracle database and use LINQ to oracle
View 1 RepliesI am trying to add a new entity and have to refernce associated data to add it. I cannot load the Referencetables. Giving "The EntityReference could not be loaded because it is not attached to an ObjectContext." How do i complete this task in Entity Framework 3.5
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i am calling stored procedure through entity model like result=ctx.spname(parmas), i am expecting 0 or 1 as a result after the execution of sp, but its returning unknown values like 178 for number records.
View 2 RepliesI am new to entity framework , it is really very good , but I want to know what is the difference between using entity framework with stored procedure or without stored procedure , which one the faster and what is the benefits for using stored procedures with entity framework.
View 1 RepliesI am making a web project now. And i meet some problems working with Entity Framework. My program needs to have dynamic model. I try to explain. So i have classes and database is created from them. At the beginning of work program checks in folder Modules for assemblies and looks for classses that needs to be created as tables in database(this classes have to become a part of ef model). And i need at runtime create database.If some new classes was added so add this tables to database, but not recreate it(as it is made by default). If i delete classes the tables are not deleted.
View 2 RepliesGenerally what is m.v.c model in software application development and entity framework in asp.net and are these diffrent form 3 layer d architecture(UI layer, Business access layer, Data access layer)
View 2 RepliesCan I generate entity framework model by clicking button in browser in client-side and save it back to web server PC?
View 2 RepliesI want to use entity framework model for visual studio 2010. I am using oracle database. i was wondering
if it is possible to use entity framework for oracle. If it is not possible then I will just use simple ADO.net and call stord proc and packages.I already downloaded oracle data provider for entity frameowrk from codeplex web site.can someone give me any example that connects to a sample oracle database and use LINQ to oracle
I have an EDM, it includes the entities extension and history. My goal is to use history to keep track of all the changes made to extension entity. For example, if extension with ID 223 has its property 'Name_Display' changed - I want the history entity to record this.
I'm using ASP.NET with VB.NET. Where in my code do I put the hook to say, "update the history entity" and what should that hook look like?
I am using C# with Entity Framework Model. I want to fill a textbox (tbPrepProbComment.Text ) with a string (S0PrepProbSolveComment) from a table (EightDProject). I'm getting the key for the EightDProject from a textbox (SelectTrackingNumber). I'm not sure my query is working because when I look at the query result ( project ) I see the error" 'mykey' could not be resolved in the current scope or context. Make sure that all referenced variables are in scope, that required schemas are loaded, and that namespaces are referenced correctly." If the query was working I dont know how to pull the field from the distinct row it should return and put it in the textbox. I've tried the line tbPrepProbComment.Text = project.S0PrepProbSolveComment; Here is my code:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.Objects;
namespace EightD1
{
public partial class Page1 : System.Web.UI.Page
{
public int mykey;
public string comment;
public object obj;
// the entity framework model
EightDdbEntities EightDP = new EightDdbEntities();
protected void Page_Load(object sender, EventArgs e)
{
SelectTrackingNumber.Focus();
}
//When the project id has been selected get projectdata and bind to page data holders
protected void SelectTrackingNumber_TextChanged(object sender, EventArgs e)
{
BindData();
}
private void BindData()
{
try
{
mykey = Convert.ToInt32(SelectTrackingNumber.Text.ToString());
}
catch
{
mykey = 0;
}
ObjectQuery<EightDProject> project = EightDP.CreateQuery<EightDProject>(
"SELECT DISTINCT p FROM EightDProjects AS p WHERE p.EightDID = mykey ");
//tbPrepProbComment.Text = project.S0PrepProbSolveComment;
}
}
}
I can't to understand clearly how to create strong and quickly application using EF. For example, I have class ForumPost (table ForumPost) for select one of record I write method like:
public ForumPost ForumPost(int ForumPostID)
{
return
(from i in _dataContext.ForumPostSet
where i.ForumPostID == ForumPostID select i).First();
}
all works. But on page (I use ASP.NET MVC) I should display info from another linked tables, ForumName (each post have ForumID) etc. So, I modify this method to:
public ForumPost ForumPost(int ForumPostID)
{
return
(from i in _dataContext.ForumPostSet
.Include("ChildPosts").Include("ParentPost").Include("Users").Include("Forums").Include("Tags").Include("ForumPostPolls")
where i.ForumPostID == ForumPostID select i).First();
}
ok, all works. Then I want to make some actions in model with ForumPost, i.e.
public void RootPost(int PostID, ref Models.ForumPost Root)
{
ForumPost post = ForumPost(PostID);
if (post.RootPost != null)
{
Root = ForumPost(post.RootPost.ForumPostID);
}
else
Root = post;
}
it works too. But problem is in speed. I not need in RootPost all those includes. So, I should to create one more method like:
private ForumPost ForumPostIncludes1(int ForumPostID)
{
return
(from i in _dataContext.ForumPostSet
.Include("ChildPosts")
where i.ForumPostID == ForumPostID
select i).First();
}
then ForumPostIncludes2, ForumPostIncludes3 etc... second way - redesign RootPost with LINQ expr, not with call another method. But in this way difficulties to change DB. third way? How to do it correctly?
I get an cast exception when i am trying to insert an entity in Entity Framework (using code-first). From this code :
public virtual T Insert(T entity)
{
return Context.Set<T>().Add(entity);
}
The cast exception is like "impossible to cast ...Collection'1(Entity) to type (Entity)" I can't figure out why. I am pretty sure ive done everything right. Post entity
public class Post
{
public long PostId { get; private set; }
public DateTime date { get; set; }
[Required]
public string Subject { get; set; }
public User User { get; set; }
public Category Category { get; set; }
[Required]
public string Body { get; set; }
public virtual ICollection<Tag> Tags { get; private set; }
public Post()
{
Category = new Category();
if (Tags == null)
Tags = new Collection<Tag>();
}................................
I am mapping a stored procedure to an entity by right clicking on the entity (in the .edmx) and selecting "Stored Procedure Mapping." This brings you to a Mapping Details - "Name of Entity" Window that allows you to select the insert, update, and delete stored procedures associated with the Entity. It also maps the stored procedure parameter to the Entity "Property" (Column).
I'm gettin an error "error 2042: Parameter Mapping specified is not valid." The cause of the error is fairly obvious, in the Insert stored procedure that has been selected, a 'CHAR' parameter is being mapped to an Int32 Entity Property. I altered the stored procedure parameter to match the entity, I deleted the stored procedure, readded, and reslected it as the Insert function. I also cleaned, validated, updated model from database. No matter what I do, the parameter list in the mapping details doesn't reflect the change to the stored procedure. It's stuck on a char --> int32 mapping, even though it has been changed, like it's buried deep in meta data some where.
I have a stupid problem with the Entity Framework. I get the following Exception:
[Code]....
I have an entity with a 4 fields representing the primary key. I copy it via serialization (works fine). I set the old entity to not valid (Datefield set to a date in the past, this field is part of the PK) and set the copied entity to DateTime.Now.Date. When I call context.AddObject I get the Exception above. I tried copying the entity via reflection but the entity has 3-4 references. And when copied, I get another Exception before even Adding the entity to the context. I also tried setting newObj.EntityKey = null and reset all the fields neccessary for the PK. I just want a whole copy of an entity with a different primary key (and some other fields changed too) and Create it in the database.
I'm writing a custom .NET MembershipProvider (not the built in one) and trying to update using Entity Framework. But of course i have no access to (Try)UpdateModel. How can i update it?
View 3 RepliesI have an Events table and an InstallmentPlans table. The relationship is 0..1 : an Event can have 0 or 1 Installment plans. If I want to remove the existing InstallmentPlan for an event, how do I do this? Setting it to null doesn't seem to work:
_event.InstallmentPlan = null;
Here's a simple code snippet where I create a new Entity object and call SaveChanges() to create a new record in the mapped database table.
[Code]....
What I'm trying to figure out is whether there is a way to derive this new key for my entity, e, from the ObjectContext, m? The reason for this is that the way my actual code is structured, my entity object is already out of scope at the point where I call the SaveChanges() method.
I am trying to do something like this:
[Code]....
But ofcourse it is not working as I want to. The Ordering works on Question.Order, but I would also the
Questions.SubQuestions List to be ordered according to SubQuestions.Order
I am using Entity framework to model my database (model first) however the table generator is creating tables with plural names. I have looked into the ssdltosql10.tt file. It is generating the table names from Entity set. Any way this can be changed to get the table names from "Entity Name" instead of the "Entity Set Name" so I end up with singular table names.P.S. BTW in Northwind Database the tables are pluralized however in adventure works database the tables are singular. I prefer singular.
View 1 Repliesrecently i've studied on ADO.NET's Entity Model Framework and say 'wow' as ORM is one of the fevourite pattern i practice..but suddenly i've come to an ambiguous situation when i'm going to start. i usually follow the following 3-tier architecture..
1. UI Layer
2. BLL - business logic layer
3. DAL - Data Access Layer
a. DTO / DAO
b. Gateway (contains the sql query/stored procedure and connection with DB)
now when i'm going to use the Entity Model Design,where the DBML/ .edmx File should be placed? Because many a times i'm using the DBML file as DTO because of the mapped objects.. in the same time, sometimes DBML ( .edmx file in .NET 4.0) contains CRUD methods and stored procedured method as well as methods with different selection operations,- which should be in Gateway. so where the .edmx file should be placed !?!! IN DTO namespace !? or in Gateway namespace!
moreover sometimes there is no need for the BLL which breaks the rules of inter-layer-communication (UI > BLL > DAL.Gateway)! what makes me confuse is, what should be the ideal n-tier architecture when i'll use the ADO.NET Entity Model Design Framework
I have been asking my self this question from the time i started workin in the software development field, What is the best way to access data? Which gives the best performance? Which is the best for maintainability? There are lots of solutions to deal with database in the Asp.Net web app,Entity framework 4.0 Classes generator using ADO.Net such as Code Author ( i liked the way it works and the way it accesses the database using the data access block in Microsoft Enterprise Library). i will start a new project tomorrow,and i don't know which approach is better?
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