ASP.NET Identity Model First fails because of renamed AspNetUserRoles columns - entity-framework

Question

Like several others I have tried to implement ASP.NET Identity Model First. Everything works fine once you have tried, errored, fumed, searched and resolved.. I thought.
See also:
ASP.NET Identity with EF Database First MVC5
http://danieleagle.com/blog/2014/05/setting-up-asp-net-identity-framework-2-0-with-database-first-vs2013-update-2-spa-template/
Course of action, summarized:
Created default project (MVC5)
Create database
Update connectionstring in the web.config
Run website, register: tables get created
Create EF Model (edmx)
Import Identity tables (everything fine up to this point)
Modified xxx.Context.tt to inherit from IdentityDbContext
Generate database script (trouble starts here)
I have solved the issues that appeared (up to the latest step). For completeness I will describe them.
Using the default Identity context
Everything works fine: tables get created, I can Register and login. This is however not the situation I want: I want to use a Model First approach.
Using the custom, model first context using the EF connectionstring
Modifying the CreatePerOwinContext so that it uses my Model First context:
public void ConfigureAuth(IAppBuilder app)
{
app.CreatePerOwinContext(CustomModelFirstDbContext.Create);
And the ApplicationUserManager so that it uses the Model First context:
public static ApplicationUserManager Create(IdentityFactoryOptions<ApplicationUserManager> options, IOwinContext context)
{
var manager = new ApplicationUserManager(new UserStore<ApplicationUser>(context.Get<CustomModelFirstDbContext>()));
Results in:
Server Error in '/' Application.
The entity type ApplicationUser is not part of the model for the
current context.
Description: An unhandled exception occurred during the execution of
the current web request. Please review the stack trace for more
information about the error and where it originated in the code.
Exception Details: System.InvalidOperationException: The entity type
ApplicationUser is not part of the model for the current context.
Source Error:
An unhandled exception was generated during the execution of the
current web request. Information regarding the origin and location of
the exception can be identified using the exception stack trace below.
Stack Trace:
[InvalidOperationException: The entity type ApplicationUser is not
part of the model for the current context.]
Using the "normal" connectionstring with the custom, Model First context
An exception of type
'System.Data.Entity.Infrastructure.UnintentionalCodeFirstException'
occurred in WebApplication1.dll but was not handled in user code
Additional information: Code generated using the T4 templates for
Database First and Model First development may not work correctly if
used in Code First mode. To continue using Database First or Model
First ensure that the Entity Framework connection string is specified
in the config file of executing application. To use these classes,
that were generated from Database First or Model First, with Code
First add any additional configuration using attributes or the
DbModelBuilder API and then remove the code that throws this
exception.
So, I figured I needed the default Identity context to use Identity, and use the custom Model First context for everything else. Not the preferred solution, but acceptable.
Rolled everything back
Import Identity tables from database
(Optional) Created entities via the Model First approach
Generated database script
Both the normal project and a quick sanity check test project have the same problem with the AspNetUserRoles table. That is a junction table, and when importing it in the EF designer, everything is OK. You won't see it since it is a many to many relationship, and when inspecting the association between AspNetRole and AspNetUser it looks good.
Designer and mapping details:
However, when generating the sql script, EF modifies the keys.
Designer and mapping details:
Generated SQL script:
-- Creating table 'AspNetUserRoles'
CREATE TABLE [dbo].[AspNetUserRoles] (
[AspNetRoles_Id] nvarchar(128) NOT NULL,
[AspNetUsers_Id] nvarchar(128) NOT NULL
);
GO
In EF, you can't change the names of the mappings in the designer (thread on social.msdn.microsoft.com).
Subsequently the creation of a new user wil fail, using the originally created context because the junction table contains the wrong columns:
Server Error in '/' Application.
Invalid column name 'UserId'.
Invalid column name 'UserId'.
Invalid column name 'UserId'.
Invalid column name 'RoleId'.
Invalid column name 'UserId'.
Description: An unhandled exception occurred during the execution of
the current web request. Please review the stack trace for more
information about the error and where it originated in the code.
Exception Details: System.Data.SqlClient.SqlException: Invalid column name 'UserId'. Invalid column name 'UserId'. Invalid column name 'UserId'. Invalid column name 'RoleId'. Invalid column name 'UserId'.
Source Error:
Line 89: {
Line 90: var user = new ApplicationUser() { UserName = model.Email, Email = model.Email };
Line 91: IdentityResult result = await UserManager.CreateAsync(user, model.Password);
Line 92: if (result.Succeeded)
Line 93: {
What is the solution? Are there any alternatives than trying to change the generated script, or moving to Code First?

Answer 1

If you in the begginning and db is still empty than
I believe the easiest workaround is:
Create EF Model(edmx).
Right click on model "Generate Database from model".
It will create DDL file (snippet below)
Replace all wrong "AspNetUsers_Id" and "AspNetRoles_Id" for correct values.
Right click "execute".
Works for me.
-- Creating non-clustered index for FOREIGN KEY 'FK_AspNetUserRoles_AspNetUser'
CREATE INDEX [IX_FK_AspNetUserRoles_AspNetUser]
ON [dbo].[AspNetUserRoles]
([AspNetUsers_Id]); //replace for UserId
Happy coding!