C# - Only Update Actually Updated Fields In Entity Framework?
Sep 13, 2010
Quite a common use case, it seems, is when re-populating an object from a form is to go
myobj.Name = "textbox value";
myobj.Content = "textbox content";
But, name may not have changed, it may only be a change to the content textbox.
The problem is that entity framework treats Name as changed just because I've set it's value, regardless of whether I've set exactly the same value or not.
Ideally, I would like EF to only mark things as changed if they genuinely have changed.
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Jun 30, 2010
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?
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Feb 10, 2011
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.
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Sep 21, 2010
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?
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Mar 17, 2010
I have created a .edmx for the northwind database. When I run the following statement, the correct number of detail records are retrieved and I can access the detail fields, but how do I access the order header record to view OrderDate, ShipAddress, etc...?
[Code]....
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Mar 20, 2011
I have been updating my Entity Framework by simply right clicking and clicking on "update model from database". I usually go under the "Add" tab and then click the tables and click finish. I also use "refresh" sometimes as well. What are the differences between these? and also when I do refresh or add sometimes the entity comes out wrong or keeps some of the old information in cache, how can I just get the entity to match my database and clean out any of the old cached things.
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Jan 25, 2011
I want to update database using entity framework by passing class object in one go with setting without setting object values again.
I have added data using following code
[code]....
here obj is class object which i have passed to the AddTotblTables() method
similary i want to update table in same manner by passing class object.
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Sep 28, 2010
I have a few entities I'd like to update at the same time. However I'd like to write individual update methods in each classes partial class file, for each entity and call them all at the same time. For example:
public sub UpdateEntity1()
...
end sub
public sub UpdateEntity2()
...
end sub
public sub UpdateEntity3()
...
end sub
public sub UpdateAll()
UpdateEntity1()
UpdateEntity2()
UpdateEntity3()
end sub
My question is how do I manage the object context? do I create one object context in the class I'm calling UpdateAll(), then pass it as a parameter to each individual update method? Or do I create a new context for each Update? I'd like to use the same context because the object are related, and this would decrease the db calls to update all the records.
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Jan 16, 2011
How should I solve simulation update, when one user updates already updated entery by another user?
First user request 'Category' entityobject, second user does the same. Second user updates this object and first user updates. I have field timestamp field in database that wa set to Concurrency Mode - Fixed.
This is how I update:
[Code]....
Exception never jumps...How should I handle this?
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Dec 3, 2010
How do I use a stored procedure to change one or more (but not all) fields of a entity in EF4? I have a stored procedure "ChangePassword" taking a username and and a password as parameters and a User entity containing properties for Username and Password as well as other properties. I want to be able to use this stored procedure from a function to update the password from a function in one of my repositories. How to do this?
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Feb 21, 2011
I have read some articles about the new enitity framework and I think it looks very cool from a development perspective.
considering a production environment loaded with data. How does one apply changes to the model? You cannot regenerate the model and in most large organizations, database changes are executed by DBS's and not developers. In such situaitons, it is the role of the developer to develop delta-scripts that the dba can execute.
My experiense with Hibernate (Java) and the like is that you have to pay double when using such frameworks.
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Mar 23, 2011
I have a webservice which of course has to be .net 3.5 (a side note is does anyone know why you can't create a webservice using .net 4.0?).
Anyhow it is using entity framework, which I have recently discovered was a really bad mistake to try to use this in .net 3.5.
I have a table "Licenses" with the following columns: LicenseKey, ProductCode, OrderID, Seq, UserName.
In my asp.net 4.0 application I can simply do the following to perform an update:
[Code]....
But it appears there is no ExecuteStoreCommand in .net 3.5 with entity framework. Can anyone explain to me how to accomplish the same thing? The thing I need to point out is that because this is a multi-user access service. I need to verify that SQL will only update the given record where OrderID and Seq is what I tell it ONLY if the UserName is already null. So if two users process the same statement at the same time only one would work and the other would not because the sql should fail (or return 0, rather than a 1) for the second one.
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Feb 24, 2013
I am using Entity Framework 4.0. I want To write a query for multiple row update.
Then how to write Query for multiple row update in Entity Framework.
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Dec 9, 2010
I've pulling back an entity object from a database and I need to update the date to the DB server's date/time - usually you could accomplish this by setting it with the SQL getDate() function.
How can I accomplish this in the following scenario:
var client = context.client.Where(c=>c.clientID == 1).FirstOrDefault();
// the value needs to be the value of the server's current date, i.e, getDate()... not DateTime.Now
client.someDate = <somevalue>;
context.SaveChanges();
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Apr 2, 2010
I have a table in my database with a one to many relationship to another table, which has a relationship to a third table:
[Code].....
This seems to work fine. My question to you good folks: Is there a correct way to do this? I tried following the making a custom model binder per the blog link I posted above but it didn't work (there was an issue with reflection, the code expected certain properties to exist) and I needed to get something going ASAP. PS - I tried to cleanup the code to hide specific information, so beware I may have hosed something up.
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Nov 22, 2010
How can i insert,update and delete records using entity framework data model.
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Oct 25, 2010
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.
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Dec 10, 2010
i want to know how to call stored procedure in entity framework. how to do code with controller class and with model.
i mean if i want to call insert,update,select,delete stored procedure for entity framework then what are stps i have to follow.
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Jun 29, 2010
I'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
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Mar 15, 2011
I created two stored procedures in SQL Server Management Studio.
First procedure add field in ProjcetsToUsers table (for many-to-many associations)
[code]....
I can delete the user from the project and then add another, and the new one is added but removed the remains.
As for data base both this function work correctly.
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Nov 2, 2010
I 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.
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Mar 30, 2011
I use a Detailsview, Entity Data Source to edit/update my table with only 3 columns.(it has primary keys).
Everything works fine inserts/edit in dev environment. but when i run this in release mode. i cannot update existing data in the database with the detailsview. whenever i update and save page gets refreshed, but nothing gets updated. but whenever i insert a new record, and then i try editing it. it works.?
Note: i handle DetailsviewItemUpdating,DetailsviewItemInserting events to do some custom checks.
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Feb 9, 2011
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>();
}................................
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Aug 5, 2010
I 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
[Code]....
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Mar 31, 2011
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.
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