I have 20 class.cs with x00s properties for my old project
and now i want to use EntityFramework
but I dont want to rewrite all this classes from begin
i just want to convert this class to DataModel.dbml or use some thing like add Existing Item
and I tried creat class with same name and copy the code inside them but the editor clear them after saving
how can i do that ?
There is plenty of resources regarding Plain Old CLR Objects and Entity Framework code first model on the web.
ADO.NET EF 4.0: Working with Plain Old CLR Objects (POCO) Classes
Code First step by step tutorial
But the gist of it is:
Entity Framework >4.0 supports POCO types that don’t need to inherit from a base class or
implement any interfaces to get persistence. There is also no need for metadata or mapping
attributes on type members, so you can use your existing code as simple entity classes.
An EDMX file that contains the conceptual model is still required. Add a new ADO.NET Entity Data Model to the project.
Using the toolbox, drag entities and associations from the toolbox and design the conceptual model. Simply make sure that the names on your POCO classes match the names of your conceptual entities.
Add entity keys as you would add primary keys in a db. Add associations like foreign keys in a db.
In Solution Explorer, click the EDMX file and then, in the Properties window, clear the Custom Tool property to turn off the automatic generation of .NET classes for your conceptual model.
Right click edmx design area and select 'Generate database from model'. DDL will be produced. Run that to create your db.
Make sure your POCO classes and POCO edmx model are in a separate assembly.
Create your custom ObjectContext derived data context with ObjectSet<T> members like here. Newer EF releases use System.Data.Entity.DbContext and System.Data.Entity.DbSet<T> instead.
You can use dbml too (Linq To Sql classes instead of EF), but you still need to generate your model from scratch, like you'd do with EF.
Related
It is possible to generate a POCO class for one selected table in entity framework.
There are few tools that does that, but it does generate for all the table,
The primary reason i am asking this is to generate a POCO class for a single table, and add attributes to it manually, and the all i need to do is to attach it to DbContext as a property :).
As for example using Package-manager, they way it is done to add migration
generate-poco TableName FileName.cs
You can use the ADO.Net wizard to generate the POCO classes for you from the database. The wizard will generate one partial class per table with properties that match your field names. Here is what I've done in the past when I wanted to add a new large table to an existing code first context.
Add->New Item -> ADO.Net Entity Data Model
Move the generated POCO classes to some other folder (and edit the namespace)
Delete the rest of the extra stuff (I.e the .edmx file and generated context)
Add the DBSet to 'your' DBContext
If you are using EF migrations
add-migration
update-database
There are a lot of extensions for visual studio for that.
EF 4.x POCO Entity Generator for C# Free (try this one and you only need to map the table)
Assumptions
Using EF 6.1, MVC 5, VS 2013, C#
I have an existing database model designed in Toad DM for SQL Server and it's very important keep it always updated
Steps and Notes
Using ADO.NET Entity Data Model I chose Code First from Database (new feature in EF 6.1) to generate the models. Note: Model classes and DbContext class generated successfuly but NO .edmx or .tt file was generated.
Next I added a new scaffold item: MVC 5 Controllers with views, using Entity Framework. Note: Success, controllers and views generated
Question
From now on I don't want to use Code First to update my database. Instead I want the models to be updated based on database changes. What to do next? If I don't have an edmx file will I not be able to update my model classes from the database?
The Entity Data Model Wizard's Code First from Database does an excellent job creating your entity classes, as if they were created in the Code First style. What you are asking is if there is any way to keep these classes up-to-date as your database changes, similar to the EDMX style "Update Model From Database". From what I've researched this is not possible using the built-in tooling. However, here is one workaround that I've found useful:
Let's say I have database with a product table and customer table. Originally I created a StoreDBContext class, and selected product as one of my objects. Now I want to add the customer table as a new entity to the existing context. Here's how to do this using the Code First Wizard:
Create a new Entity Data Model, call it StoreDBContextTemp or whatever
Choose the code first from database wizard option
Select customer as an object to add (just customer) & complete the wizard
Open the newly created context file, StoreDBContextTemp.cs, and copy the virtual properties of your newly added entities:
public virtual DbSet<Customer> Customers {get; set;}
Paste these new properties into your Original StoreDBContext.cs dbcontext class.
Delete StoreDBContextTemp.cs, and remove the connection string for StoreDBContextTemp in app.config/web.confg etc.
You can now use Customer on the StoreDBContext class
If you add or remove tables you will need to manually adjust fields, but at least you won't need to hand write dozens of properties each time a new table is added to the model.
One more option is just delete the auto generated classes from the project and once again generate them.
While following this approach only thing we need to make sure that is we should give the same name for the data model(class name which inherits from DbContext ) as the previous one.Data model name is highlighted in below snap
Three things.
There's no .edmx when you use Code First.
If you use Code First Migrations you would have to write first the code and after that migrate the changes to database. This helps you to have much more organized you code with no generated code which is an advantage.
There's a plugin in Visual Studio for doing contrary. Entity Framework PowerTools allows you to select the database and map it to objects.
https://visualstudiogallery.msdn.microsoft.com/72a60b14-1581-4b9b-89f2-846072eff19d
The best solution to me is deleting the model and recreate updated one with the same name, keeping in mind two points:
Personal extension methods implemented for the model;
Possible manual relationships between tables added to the model because of not setted up in the phisical db.
My personal solution:
Move all extension methods to another partial class that won't be overrided;
Insert all added properties of an entity to another partial class;
Keep track of all manual relationships in an help file, so you can add them again being sure not to loose anything;
Delete the old model and recreate one new with the same name and update it with the manual relationships of point 3.
I want to convert my code-first project to Database first. Is there an automated way or should I just delete the entities and context code and create a model from the created database?
It appears Entity Framework Power Tools supports a feature called "Reverse Engineer Code-First". You can download it here.
There is no way to convert your code-first classes into database-first classes. Creating the model from the database will create a whole new set of classes, regardless of the presence of your code-first classes.
However, you might not want to delete your code-first classes right away. The entity framework database-first model creates partial classes for all of the entity objects. If you have any business logic (anything besides the plain old properties) in your code-first classes, you can declare them as partial, remove the properties, and maintain the business logic. Essentially, you're letting EF generate the properties in the *Designer.cs file, while you define the business logic in your .cs files.
I'm building an application using EF 5 to talk to an existing Oracle database. I'm not allowed to change any part of the DB schema. I have generated my model from the database using the VS2012 wizard, and all classes are named after their Oracle counterparts.
The naming of objects in the database is QUITE_UGLY_AND_INCONSISTENT, so I'd like to rename the POCO classes and properties. I can easily do that from the EDM Designer. As a result, I get neatly named class and property names, that are mapped to the UGLY_NAMED tables from the DB. I can successfully perform queries and everything works smoothly. Exactly what I wanted.
However, when I need to add new tables to the model, I run the "Update Model from Database" wizard and check the additional tables to import. It suddenly lists my renamed (but still correctly mapped) classes under the Delete tab, saying it can't find them in the database. When I click Finish, my existing classes are unmapped and I have to manually re-map each property to its corresponding DB column... Or roll back to the previous version of the EDMX file from version control.
I'm looking for what you think would be the most elegant solution to this problem, since I need the application to be as maintainable as possible. I strongly favour an approach that lets me auto-generate new classes from the database while preserving the existing renamed objects and their mappings.
Am I overlooking some way to prevent the Update Model wizard from deleting my existing mappings?
Should I use a different approach to renaming the generated classes?
Should I leave the generated classes unchanged and instead construct sanely-named wrapper classes that are exposed to the rest of my application?
Should I refrain from auto-generation and instead go for a code-first approach? This is a very unfavorable option, because I need the time spent on manual model coding and mapping to be as little as possible. Adding objects will be a very frequent task.
Should I perhaps even use a different ORM altogether..?
I discovered the culprit myself: running the "Generate Database from Model" wizard due to a recommendation in an article I read somewhere. It changed all the model's underlying table and column names to SQL Server standard names ([dbo].[Customers].[CustomerID] etc.).
I have 3 tables in my MS SQL database and I have added a EntityFramework(latest) to my project where I have imported these 3 tables. The first problem was that no Entities was built so I changed "Code Genereation Strategy" from None to Default.
After build I get
X Already Contains a definition for Y
on all properties of the entities.
When looking closer it have generated a partial ex Users.cs and one partial User in in the MainModel.Designer.cs?
Why is it generating User.cs? I have a similar setup in another project and the EF is set with the same settings, there is no User.cs?
Edit1 : I can see one thing that differs and thats Use Strong Spatial Types that is set to False in the failing project, it is however not possible to set it to true(grayed)?
You should either use None code generation strategy for your .edmx file. Or remove MainModel.tt and MainModel.Context.tt templates, which generate model entities and context.
If you use Default code generation strategy, then entities and context will be generated into MainModel.Designer.cs file. That would be standard entities, inherited from EntityObject, context will be inherited of ObjectContext. With Entity Framework 5 we have POCO entities generation. And whole generation is done in T4 templates, which generate context, inherited from DbContext, and POCO entities without some base type (well, object only).
When you have both templates and enabled code generation in edmx designer, then two sets of entities will be generated. That's why you have names conflict.
Right Click the Entity model.
Go to properties and remove the default name in the "Custom Tool".
Assign the edmx in the model.tt and model.context
Build and execute it you will be free from error.