Using Entity Framework 6 Code First in an ASP.NET project with Visual Studio 2013, is there any way to rebuild (or update) the generated DataContext and model classes without stepping through the Entity Data Model Wizard every time?
I'm fully aware of how to do this with an EDMX designer, but again, I'm using the "Code First from database" method and just wondering if there's a one-click (or one console command) way to trigger the rebuild without having to delete the generated context class and then step through the Entity Data Model Wizard every time I make a change to the backing database.
In VS 2015 (and supposedly 2013/2012) you can use the Entity Framework Reverse POCO generator to accomplish this.
https://visualstudiogallery.msdn.microsoft.com/ee4fcff9-0c4c-4179-afd9-7a2fb90f5838
You can make all your changes to database first, and to re-generate your models all you have to do is save your Database.tt file (usually I just add white space).
Code first requires you to create the DataContext by hand. You don't create/change the database and refresh the DataContext class. The Code first from database or EF Reverse POCO template is a middle ground between true Code First and the Database First approach of doing things. It meets at the middle by generating the same kind of POCO classes that you would have written by hand in Code First. They don't do it in Code First way but the end result is something similar to Code First. Hence the confusing name.
If you are using one of these templates to generate POCOs, you can right click on the t4 template file and click Run Custom Tool. If that doesn't work, you might want to delete that entity and then run the custom tool again. Also right clicking on the EDMX and clicking 'Update Model from Database' should work.
I have the solution for rebuild without wizard:
using the t4 is Transform All T4 Templates
and create the classes
Related
I want to create an Entity Framework Model based on database using VS 2015.
There is some problem:
1) When I want to create model I get this warning:
2) When I create mode some file being generate like T4.
3) Generated class hasn't Data Annotations like :
[EdmEntityTypeAttribute(NamespaceName="SomeModel", Name="tblCode1")]
[Serializable()]
[DataContractAttribute(IsReference=true)]
4) In our group there are some people that have VS 2013 or 2010 that they can't use this type of models.
How I can create model using VS 2015 like VS 2010 or 2013 without T4 (Just 2 files like below)
Short answer:
You need to change the Code Generation Strategy property of the edmx from "T4" to "Legacy ObjectContext" and delete the .tt nodes from the Solution Exporer.
Long answer:
Here are the steps needed:
(1) Assuming you start by selecting "Add -> New Item -> ADO.NET Entity Data Model -> EF Designer from database".
(2) Follow the "Entity Data Model Wizard". The next is very important. When you get to the screen which asks you for the EF version you want to use, make sure you select EF 5.0, otherwise T4 template will be the only option you have:
(3) Finish the wizard. Say OK to security warnings like your first screenshot. The project structure will look like your second screenshot.
(4) Open the edmx file in a designer. Look at the Properties Window, there is a property called Code Generation Strategy which by default is "T4"
Change the property to "Legacy ObjectContext"
(5) Delete YourModel.Context.tt and YourMdel.tt nodes from the Solution Explorer and you are done.
A bit boring, but does what you want. The drawback is that you are limited to an outdated EF version, and the upcoming EF7 will retire edmx at all, so it might be a good time to start thinking of switching to the Code First approach. But until then, hope the above will help to keep your current process.
For generate "Code first" model (obtain a code first model starting from database) you can also use Code Smith Generator. You can start from POCO classes templates (or from NHibernate templates if you need serialization, IDataErroInfo, INotifyPropertyChanged, and so on implemented) and customize them is really simple (the syntax is based on ASP). Probably there is also a free version.
Looking around I found also an article and an open source tool that extract POCO classes from SQL Server database.
http://www.codeproject.com/Articles/892233/POCO-Generator
In a class library Ado.net Entity Data Model is has generated POCO classes. These were generated fine for the first time. But database changes are not being reflected. In edmx diagram right clicking and choosing Update Model from Database show newly created table but it do not add table even after selecting it to add.
I tried running .tt (by right click and Run custom tool) but even it did not regenerated the Poco classes as per latest DB changes.
Help please
Not a fix but a workaround: Is it not an option to simply remove and regenerate the EDMX and the generated classes? That's what I do, it is much easier than working with the update feature, and the result seems to be the same. Your POCO extensions still remain the same and functional.
I use database first and I have my SQL upgrade scripts, the generated EDMX and my Generated models in source control and the changes there are very easy to manage. Here is a rough outline of my DB upgrade process for each version:
Create .sql script for the upgrade, statements like CREATE TABLE etc.
Delete generated files: Model.Context.tt, Model.tt, Model.edmx
Remove Entities string from Web.config (if you use it)
Create the EDMX and Context files the same way you did for the first time
If you use source control (I hope you do!) check what has changed
Test
Commit!
In my case i needed to save ModelName.edmx, then classes were generated.
Ensure that connections string in app.config is correct. I was using a DataDictionary and my connection string had the following path:
data source=|DataDirectory|*.sqlite
Thus, it wasn't updating. Because this DataDirectory variable was being resolved at runtime.
I have added added Entity Framework to my project and selected Code first from database when creating my models. But the problem is, i couln't find how find how to update existing models and add new models to my project when i make changes on database.
It is very straightforward. Switch on migrations, change/add you classes, create a migration and update your database. See here for example. There are plenty of other sources.
When you change your DB you can run the EF generation again but it will overwrite the existing files so you will lose any changes. If you want to maintain code outside the generated files then you can use partial classes. Or alternatively just code them by hand after the initial auto generation, it's quick once you get used to it! :)
We have a fairly elaborate data model built from an existing database, then enhanced using partial classes to support additional methods & properties, inheritance, etc. We have not yet bitten the bullet to update this from ObjectContext to DbContext.
I am using VS2012, .net 4.5, EF 6.0.2, and have installed the EF 6.0.2 Tools for VS2012.
Following the recommended mechanism to update a project to EF6 (http://msdn.microsoft.com/en-us/data/dn469466) has been successful, including the addition of the EF 6 Entity Object generator as the code generation item.
Subsequent to making this change, I would like to update the model from the database to incorporate some recent schema changes into the model. Running through the "update model from database" dialog, what appears to be happening is that an entirely new dbcontext-based model & template is added to the project, in addition to the object context-based model that already exists in the project, and none of the changes are incorporated into the entity-object template.
Of course, this means there are hundreds of duplicate names defined in the project once the operation completes. The edmx properties do not appear to have an option that would control this behavior.
Certainly, making the transition to dbcontext is the right avenue ultimately, but would like to avoid taking that on imminently.
My experience is open edmx file in visual studio by double-click and then select all tables perform a full delete(press del). Then click save button on top of menu bar, it should delete all models automatically.
After it's done, then you can update model from database again.
Hope this helps.
Now that i have generated 19 code-first classes from an existing database by:
Creating a Model-First Entity, and choosing "Generate from database"
Right clicking and choosing "Add Code Generation Item"
EF 4.x DbContext Generater
All the classes i want are generated, and I'm very happy with them...
And now for my question(s)
Why are they all the generated .cs files nested in a sealed .tt collection?
Why can't i copy paste them out to any folder i like, and treat them like normal classes?
Is it just me, or are you unable to use migrations "update-database" when you do it like that?
I guess my overall question is, why are they located in a .tt folder?
And how shall i update my database now? By editing the database manually and then update the Model, and then generate the dbContext again? Or is there a trick to get .cs files out of a .tt folder?
How do you modify you database after generating your DbContext?
Why are they all the generated .cs files nested in a sealed .tt collection?
Your code-first classes are not code-first classes. They were generated based on your database schema. Hence, this is a database-first approach. With database first, your entity classes are generated based on the database. In other words, the database comes first, the code comes second. The .tt file is a T4 template that decides how to generate your classes based on the database. You could change the database and then regenerate your entity classes.
Why can't i copy paste them out to any folder i like, and treat them like normal classes?
Because they are generated files, based on the T4 template.
Is it just me, or are you unable to use migrations "update-database" when you do it like that?
This part of your question I can't answer for certain, and will have to defer. However it seems to me like you want to mix and match approaches. It sounds like you want to start by generating code classes based on your database, and from there forward, change the database based on new entity classes you add to the model project. Is that right?
You can forgo the code-generation part and just go with a pure code-first approach, now that you have an idea of what the entity POCO's should look like. I have tried this T4 code generation before (pre EF 4.1) and immediately abandoned it, because as you have seen, since the entity and DbContext classes are generated, you lose control over the object-oriented model.