I am creating an MVC project with .NET. A database already exist and I'm using the Entity Framework to access the database.
One of the tables in the database is called "System". EF therefore creates a class by that name. This obviously a conflict with the "System" namespace.
Renaming the table is not practical at this point. Is there another way I can use EF for my project?
Thanks
It's not a problem, you simply need to reference the class through its namespace.
e.g.:
If your generated entity class is under the namespace AppName.EntityModel, the following would work
global::AppName.EntityModel.System
AppName.EntityModel.System
EntityModel.System // if already under the AppName namespace
Related
I am new to both MVC and the simple membership that comes with ASP.NET.
I have been following tutorials and I have been able to create the Simple membership tables to work in a custom db along with my own tables.
I ran into a problem when I tried to use the ADO.Entity Model to create classes so i could access the database data. When i tried to run the application after creating the entity models i got an error. I think it is because the ADO.Entity Model created classes with the same name as classes all ready in the app???
Error 1 Missing partial modifier on declaration of type 'MvcApplication5.Models.UserProfile'; another partial declaration of this type exists C:\Users\user\Desktop\MvcApplication5\MvcApplication5\Models\AccountModels.cs 22 18 MvcApplication5
Any help would be greatly appreciated
Thanks
SimpleMembership uses EF code-first so you do not need to create the classes, they are already created by the T4 Internet Template. The class that represents the UserProfile exists in the file referenced in your error message. You are getting an error message because you are trying to create a duplicate of the class that already exists. Take a look at this article on how to customize SimpleMembership.
I have entity framework classes generated using the update from database option and model classes that I have created. My question is if I have a table called 'car' and have a model called 'car' as well what is the best way of using these? Should they be the same class or should I use partial or should I have separate class for the model and separate class to represent the database table can you point me to an example?
I've always kept view models in a separate class library (with a separate namespace) from the entity data models. This way if the database schema changes (which almost always happens) I'm not breaking my views. And to move data between the data objects and view models I'm rather fond of Automapper. It'll even give you unit test failures if there are properties on a destination object that you are missing a source mapping for, helping you catch errors early.
I've found it's normally good practice to have a separate project in your solution specifically for data access.
I normally set this up as a class library project with something similar to the following structure.
/ProjectNameData
/Models/ -- POCO's go here
/Mapping/ -- EntityTypeConfiguration classes go here
/Repositories/ -- Repositories go here
/ProjectContext.cs
Then I would have another class library for services as well as my main application project.
I am currently developing project using C# MVC and entity framework, I want to use the entity framework in other modules ,
i.e security module , Utility module ,
i want to call the db using the entity frame work, how do i do this ?
i am new to this are please explain in detail, idea is to break the project into presentation layer, business layer and data access layer..
i don't know how to archive this.
Try this way,
There are three ways to work around entity framework, Database First, Model First & Code First.
Database First: If you already have database, then entity framework can generate a data model that consists of classes & properties that correspond to existing database objects such as tables & columns.
The information of database structure, conceptual data model & mapping between them is store in the xml in an .edmx file.
Model First: If you don't have database, you can start creating model using vs entity framework designer. This approach also use the .edmx file.
Code First: In this approach, we don't need .edmx file. Mapping between store schema & conceptual data model is represented by code, handled by code convention & special mapping API.
Here I have used the Database First approach.
In order to use the Dal class lib, add the reference in the business logic layer and initialize the entities class. For example
Find the entity framework object.
Initialize the entity framework object in other class lib.
FrameworkEntities entities = new FrameworkEntities();
Please let me know, if you want to use model first or code first approach.
Get started from the below link for the Entity Frame Work
http://msdn.microsoft.com/en-US/data/ee712907?
I have generated xxxModel.Context and xxxModel template (in Models) from an existing database using EF 4.1 on ASP.Net MVC 4 application. After that when I build the project it gives the error for all the Model classes (POCO) saying "The type file name already contains a definition for memeber variable name". Where am I going wrong?
Thanks for help.
Clearly the file DESE.cs (and others) already contains identically named classes with properties - which are clashing with the types generated by EF. CC_Names.cs, for example, is being output by a text template - so I'm assuming you've got more than one code-generation strategy going on here from the same database.
And then you also have issues where you've re-declared the partial class CorpCostEntities again in another file with a different base to the one set by the EF code generator.
I think you might need to decide whether you want to use edmx code generation or the text-templating approach and stick to it :)
I have created mvc3 application.
I have one .edmx already created which is based on Db1 but now
I have created a view which is based on Database2 and I need to use this view inside my project.
For that I need to update my EF .edmx file.
but when I right click and select option Update model from Database
i'm only getting all tables , view ,sps fromDb1` its obvious
But as i need to use view which is fromDatabase2how can i add it into my model.edmx` file?
please help.
If two edmx want to merge then make partial class same for both edmx file (there will be two designer classes). Add another constructor and make it parametrized, for other edmx file. Parameter to identify which edmx want to load.
Add another class file in Business layer create object of edmx partial class in this class file, Under this class when ever you want to load whom so ever edmx file pass some argument in constructor of edmx partial class constructor to identify which connection needs to open.
Pass parameter in constructor of edmx designer class, based on decided page name (custom logic or table name; That edmx will get loaded.
In web config file multiple connection strings will available for multiple edmx file.
Entity Framework does not support mapping more than one database to one model/.edmx file (see See : unify two models (edmx) with visual studio 2010)
So you'd need to create a separate .edmx file/model for the other database, and reference each model with separate contexts. You'll need 2 connection strings in your projects as well.
One "hack" might be, for i.e. MS SQL to link these two servers and expose the data from other one on first one, i.e. via view. But I think it's manageable only for few tables. With huge models this will be pain. Other databases (Firebird, Oracle, ...) support this in similar way.
What I have done , created stored procedure in db A and accessed the db B through that SP , say select * from db2.table.then create a function import for that particular SP .
This approach works well if you have both databases on same server. In case these are on different servers you can create Linked Server on B to access A using the same stored procedure approach.
Using ctx As New Entity()
ctx.Database.Connection.ConnectionString = conString
End Using