How to update only one table for model from database with Entity Framework? - entity-framework

I have a model generated from db with Entity Framework. When I have any change in database, I update model from database to get the change in model. But this update is applied to all entities (tables) included in model.
Now I add a new column in a table Tab1. I don't want to update model from database as some other changes that I don't want to include in model. I can add the new property in model for entity Tab1 manually. then it caused mapping error.
So I need to update Model.Store for the table to include the new column. It means I want to update model only for Tab1.
How can I do this?


The EDMX file is an XML file that is a combination of 3 different parts that make up the whole thing. If you right-click on your EDMX file and choose "Open with... XML Editor" you'll see the 3 different sections:
<edmx:ConceptualModels>
<edmx:StorageModels>
<edmx:Mappings>
These sections can be edited manually, at your own risk! :-)
That way you can modify only what you need to.
Note that it's also possible to generate CSDL, SSDL & MSL files rather than having them embedded in the binary file, by changing the "Meta Artifact Processing" property of your model to "Copy to Output Directory".
If you don't want to do this manually, there's the Huagati DBML/EDMX tool, it is free and you can download it from huagati official site or from visual studio gallery, which is a Visual Studio plugin that allows you to select what changes need to be done.


I use following (Conditional) trick. This could be done only when no Table depends on the table which you want to update.
Delete the table which needs to be updated.
Right click on Model and select 'Update Model From Database'. The Table would be shown in the tab 'Add'. Select this table and Update the model.
Precaution : If other existing tables have changes in them, EF would update these changes as well.


There is way of doing it automatically.
right click edmx file > update model from data base > Refresh tab > Tables > select the table(you want to update) and press finish that's it.

Related

Entity Framework database first adding new table to exist .edmx

I added a new table to the database. In the .edmx (where database diagram is at), I right-clicked and chose 'Update Model from Database...'. I can see the new table's diagram has been generated, but how do I add model to EXISTING .tt? I know I could do it manually, but I would like to know how to generate it automatically. Thanks.
EDIT: I got the model class by clicking around. I think it was right clicking on .tt then 'Debug T4 template' which generated it. But can anybody explain what did this Debug T4 template debug?

Adding a New Column to an Existing Table in Entity Framework

I have added a new column to a table in my database. The table is already defined in the existing Entity Framework model. I've been through most of the items here on how to do this and it still fails.
A little background, this entity model has not been updated in at least 3 years. So aside from the column I'm adding I know there have been a number of other columns that have been added in that time, but never included. I took over the project about 9 months ago and have never been able to successfully update the model.
First attempt:
Opened the Model in Visual Studio
Right Clicked on the Background
Clicked on "Update Model From Database..."
Clicked on the Refresh Tab
Selected Tables
Highlighted the specific table
Clicked Finish
Result:
Classes for Dozens of tables that were in my model were deleted
The table in question was not updated
Second Attempt
Restored all Source
Same as above but
After opening the Update Wizard, Clicked the Delete Tab
Selected Tables
Clicked Finish
All the Tables were deleted
Saved the EF Model/Closed/Opened it
Went back to the Update Wizard Add Tab
Clicked Tables
None of my tables were displayed when I expanded everything
Checked the checkbox at the Tables level
Result
None of my tables were added back, but anything that was not
originally included was added
Third Attempt
Restored all source
Deleted the two .tt files
Opened the Update Wizard
Clicked Add for Everything
Result
Nothing was recreated, no .tt files or anything else.
Fourth Attempt
Restored Source
Deleted Table from the EF Model
Opened Update Wizard
Clicked Add Tables
Results
Classes for Dozens of tables that were in my model were deleted
The table in question was not added back
Final Attempt
Added entity manually to model
Result
Code all compiled and ran, but values were never retrieved from the DB or updated
Any help or direction that could be provided would be greatly appreciated as I'm at a critical point and have to get the model updated.

The "Update Model from Database" is hard/slow to use and is prone to errors. It generates other stuff that you probably don't want/need. So manually adding the column that you need will work better.
I suggest you do it outside the VS editor since depending on how many models/tables, it can be very slow opening the file in VS.
So in Windows Exlorer, right-click on the *.edmx file and open with Notepad (or Notepad++/Textpad).
Search for the text <EntityType Name="YourTableNameToAddColumn">.
Add the property <Property Name="YourNewColumnName" Type="varchar" MaxLength="64" />
Search for the text <MappingFragment StoreEntitySet="YourTableNameToAddColumn">
Add mapping to the new column <ScalarProperty Name="YourNewColumnName" ColumnName="YourNewColumnName"/>
Save the *.edmx file

Right click on the *.edmx file and open with Visual Studio's XML editor (or Notepad/Notepad++/Textpad).
Search for the text <EntityType Name="YourTableNameToAddColumn">.
Add the property e.g.: <Property Name="YourNewColumnName" Type="varchar" MaxLength="64" /> (these ones are SQL types, see existing columns for an example of how they should look).
Search for the text again <EntityType Name="YourTableNameToAddColumn">, there is a second one.
Add the property e.g.: <Property Name="YourNewColumnName" Type="String" MaxLength="64" FixedLength="false" Unicode="true" /> (these ones are EF types, see existing columns for an example of how they should look).
Search for the text <MappingFragment StoreEntitySet="YourTableNameToAddColumn">.
Add mapping to the new column <ScalarProperty Name="YourNewColumnName" ColumnName="YourNewColumnName"/> (Note: these are in reverse order, newest first)
Save the *.edmx file
After that update the edmx model of your table in the (auto-generated) entity framework .cs files public string YourNewColumnName { get; set; }

An addendum to the answer by alltej above, and answering Chris Walsh's reply that he is getting 'The conceptual side Member or Property 'xxxxx' specified as part of this MSL does not exist in MetadataWorkspace." on the new Scalar property line under '
You have to make sure that you search 'Add the property ' in TWO places within your .edmx file , otherwise you will get Chris's error

Figured out the problem. When I generated the model I was getting an Error 113:
Multiplicity is not valid in Role.
I didn't notice it among the other 16307 errors that were generated when the creation failed. Once I fixed that everything worked fine.
Thanks

I just found this question when I had a situation where I added some columns to a table, and my edmx file would update just fine; however, the code generation was not triggering properly, so my .cs files were not updating. I right clicked on the Entities.tt file and selected "Run Custom Tool" which runs the text transformations, which fixed it for me.

I ran into this problem a while ago and was able to deal with it by removing the particular table from the model, then doing the "Update model from database" step, selecting that table.

Make sure your 'Model.edmx' file has the name same as 'Model.tt' if not, just rename it the same name with the *.tt file. Then delete entities from designer and import again by 'update model from database'.

Can't select the database when updating EF model

I have an edmx model
I right click on it and select Update model from database
The wizard show up .It normally show me Choose Your Data Connexion, but not anymore. Now it show me directly Choose Your Database Objects
How can I select a different database ?
PS: When I create a second edmx in the same project and want to update it, the second one works like it should

After some trials, I found it.
You must delete the connection string in your config file (app.config in my case)

Entity Framework - Entity not added to design surface

I attempted to update my edmx file by selecting a table. The tool spit out a info message that said the table did not have a primary key.
The entity did not get added to the design surface but it did get added to the .edmx file. In addition, using the model browser I see an Entities.Store and an Entities. My table got added to Entities.Store, but not to Entities.
I cannot access the table that was "added" in the code.
What do I do?
Steps to reproduce:
Create a SQL table with two columns that are both defined as foreign keys to other tables. Make sure the tables that the FKs point to already exist in the model on the design surface.
Right click and choose Update Model from Database...
Next. Under the Add tab, mark the new table under Tables
Click Finish.
An association will be created and it will be selected on the design surface, but it won't start with FK_, it will just be the name of your table. Go to the Model Browser and look under Entity Types. The table will not be there. Look under Associations and you will see your table name there as an association, but it will look out of place (because of the name).

Entity Framework was too smart for me. It created an association instead of an entity. Odd, but it works for how I need to use it.

Entity framework 4 updating the model when a table changes

I am using Entity Framework 4.
I have my model file with my tables on it. If I go and add a new column to one of my tables (in SQL Server) how do I update the table in the model without having to go and delete and re-adding it to the model?
Thanks

There is an option when you right click anywhere in the model (*.edmx): Update Model From Database...
Then a wizard will look for any differences (Add / Refresh / Delete). So if you need to update a table, go to the Refresh tab and select your table.
Mind you, this is only possible in an Entity Framework model, not in a LinqToSql model.