DataContext - LINQ to SQL - c#

I deleted a column from a my ms sql database but my web app is still recognizing it. I believe I need to regenerate my datacontext since I'm using LINQ but I can't find a way to do so in Visual Studio 2012.
Can anyone assist me?
Thank you.

Try This :
Open datacontext model and right click on the entity (Table) and click update.
If it doesn't work then you need to regenerate the datacontext or need to delete the column manually from the model.

If you have a .dbml file in your project, then it will need to be edited to change the DataContext subclass responsible for allowing LINQ to SQL to communicate with your database. Open it in the editor to see a diagram of the tables in the DataContext. Right-click the column that has been removed, then click "delete" - this will remove all reference to the column.The project will need to be rebuilt once this is done.

Related

Database changes not propagating to entity model

I'm using EF5 with C# and SQL Server 2012. We're using database first. I made some changes to the database, added a couple views and a few table columns.
When I go into the edmx file in Visual Studio 2012 and select Update Model From Database everything is shown in the model view. The new views are present as well as the new fields.
But none of the new elements propagate into the auto generated model.cs file. I've updated the model from the database multiple times and rebuilt the solution many times as well.
Is this a bug? Is there a workaround?
Right-Click on the tt-files (one for the dbcontext, and one for the containers) that is connected to your edmx-file. Click "run custom tool". This will rebuild your containers

Update MVC database first to reflect db changes

i'm new to MVC and have to update my model.
I have an SQL Server database already connected to my project, today I add a new column. Now I need to update my MVC code to reflect the change.
Everything online tells me to update the .edmx and .tt files with the Update Model Wizard since they are auto generated, but I cannot find the wizard in VS 2012 so I am at a stand still.
Is this the right way I should be doing this? Any tips would be great...thanks
There are a couple options you can do:
If the database is empty or there isn't a lot of data that you care about, you can drop the database and recreate it.
Manually add the column in the database (after property is in model)
There is something called Code First Migrations. This will allow you to update your database. Here is a tutorial you can look at for this: http://msdn.microsoft.com/en-us/data/jj591621.aspx
Double click the edmx file. This opens the diagram of the database model.
Right click and select "Update Model from Database..."
That will start the wizard you're looking for.
Be aware that not all changes come through automatically.
Most obvious is that columns will not be removed from model just because they're gone from the db. If you're dealing with lots of modifications or deletes rather than additions, it may be best to just drop the model and recreate it (as suggested above by Andrew).
No matter which approach you take, I'd suggest making sure you have all other local source changes committed or shelved before starting because you may need to do an undo check out if EF gets freaked out.
I ended up downloading this update of VS 2012 and repaired. Now I am able to update my model.

Databases in winforms c#

I can't understand how to manage database with Entity Framework.
I'll try to describe my problem step-by-step
create winforms application
add database (.mdf) to solution
when appears window "choosing database model", select dataset
then finish, as database is empty
go to server explorer, choose created database, create some tables
add to solution EDM ADO.NET
The problem is that new data doesn't appear in my database in server explorer. This means that while my Winforms app is working, I can modify my database (change existing values, add new, ..). but if I close my app, there is no update in my database in server explorer. I DON'T forget to use function SaveChanges()
P.S. while my app is working, values are updating. Think, that means that data updates in dataset, but not in database. if i am right, give a clue how to update database from dataset.
pps. visual studio 2010 ultimate. sorry for english
dbentity db=new dbentity();
db.items.addobject(new item() {value=something});
db.savechanges();
Don't add the database to your solution. You can use the Server Explorer to add a connection to your database via your existing SQL Server, or you can select your database in the wizard that appears when adding a new EDMX file to your solution.
Did you try either of these? Where did you get stuck?

.NET 4.0 EDMX Generate DB from model and then Execute SQL removes the DATA from Table

I'm newbie with .NET Entity Framework 4.0 I'm using VS2010 and I created the EDMX file and then added my Entities in this model. After I've finished my Datamodel and set the Asscociation, I right click on and choose Generate DB from model.
Then it creates SQL scripts *.sql then I open the SQL and right click on Execute SQL Statements... What happens is all my tables are re-created...
ISSUE: All my test data in MasterData Tables are removed/deleted. I need to add the data back again manually...
I googled on "keep data generated Data model EDMX" etc. but couldn't find... Can someone advice me how I can avoid this problem?
Because I've e..g 15 MasterDataTable + other tables linked with these and I need to re-add the records back manually for all these tables... and 9 of 10 case I don't touch those tables in UI.
please advice how I can avoid this situation.
thanks
You can update the model from the database (the reverse way you are taking now):
Double click the .edmx file to open the designer. In the middle of the designer, right click to show the contextual menu and click "update model from database". It will prompt a screen, check the DB parameters and click next. Now, you're in a sreen with TABS. The first tab is for adding tables as entities to the model. The second tab will its for update the model. Select the tables and views you need to add/update and click next. That's all.

How to quickly refresh ADO.NET Entity Data Model?

I am using ADO.NET Entity Data Model in my C# project. There is an ADO.NET Entity Data Model that is generated on the DB in my project. How do I quickly refresh the ADO.NET Entity Data Model based on DB changes? I have been deleting the model and then creating a new one. I believe that there is a more simple and quick way.
Right-click on the model designer and choose "Update Model from Database", and a dialog box will pop up. Click OK and your model will be refreshed.
FYI, I'm using EF 4.0, and I skipped the earlier version, so I can't tell you what it's like in VS 2008.
Update Model from Database doesn't work very well. At least in VS 2008/C# 3.5. I fails to remove old columns, etc.
I always Ctrl-A (to select everything), the press delete, and then create model from database from scratch - update just doesn't work right in a lot of cases. At least in EF4 / VS2010 that I am developing in/with.
Perhaps this helps... Update Model Wizard (Entity Data Model Tools)
You should open your Model.edmx after that right click on the properties. now select the (Update Model from Database) and it will going to show you another panel with tab panel. you can choose Add,Refresh and delete. in your current situation, you should select Refresh. then select Tables->dbo->and name of your table in database and then click finish. that's it. you've refresh your table.
but sometimes you can see in your model that something went wrong because the column is not in right position. to solve that just right click the column name and select 'UP' to move it up or 'DOWN' to bring it down.
i hope that it will help.
Right click - Update Model from Database.

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