The model backing the ApplicationDbContext context has changed since the database was created

Question

First of all  I have not seen this error anywhere else and I guess it s not a replicate so please read the whole situation first   Everything was working just fine then I tried to update one of my model classes   the App class and the update is now left commented   which I will be listing below  and boom I had this ugly error         The model backing the  ApplicationDbContext  context has changed since the database was created  Consider using Code First Migrations to update the database  http   go microsoft com fwlink  LinkId 238269   at System Data Entity CreateDatabaseIfNotExists1 InitializeDatabase TContext context  at System Data Entity Internal InternalContext  lt  gt c  DisplayClassf1 b  e   at System Data Entity Internal InternalContext PerformInitializationAction Action action  at System Data Entity Internal InternalContext PerformDatabaseInitialization   at System Data Entity Internal LazyInternalContext b  4 InternalContext c  at System Data Entity Internal RetryAction1 PerformAction TInput input  at System Data Entity Internal LazyInternalContext InitializeDatabaseAction Action1 action  at System Data Entity Internal LazyInternalContext InitializeDatabase   at System Data Entity Internal InternalContext GetEntitySetAndBaseTypeForType Type entityType  at System Data Entity Internal Linq InternalSet1 Initialize   at System Data Entity Internal Linq InternalSet1 Include String path  at System Data Entity Infrastructure DbQuery1 Include String path  at System Data Entity QueryableExtensions Include T  IQueryable1 source  String path  at System Data Entity QueryableExtensions Include T TProperty  IQueryable1 source  Expression1 path  at Microsoft AspNet Identity EntityFramework UserStore6 GetUserAggregateAsync Expression1 filter  at Microsoft AspNet Identity EntityFramework UserStore6 FindByNameAsync String userName  at Microsoft AspNet Identity UserManager2 FindByNameAsync String userName  at Microsoft AspNet Identity UserManager 2 d  12 MoveNext   --- End of stack trace from previous location where exception was thrown --- at System Runtime CompilerServices TaskAwaiter ThrowForNonSuccess Task task  at System Runtime CompilerServices TaskAwaiter HandleNonSuccessAndDebuggerNotification Task task  at ControlPanel Web Controllers AccountController d  2 MoveNext   in d  Projects FULL Control Panel ControlPanel Web Controllers AccountController cs line 56   At first I thought it might be a migrations problem  so I dropped the database entirely  re-enabled the migrations  and added an Init migration and updated the database using   update-database -force -verbose   Everything goes well with no complaints  however  whenever I try to log in to my site I get the previous error  I did the migration thing about ten times without being able to solve the problem   Here are my domain classes   models     public class App        Key       DatabaseGenerated DatabaseGeneratedOption Identity       public virtual int AppId   get  set           Required      public virtual string FacebookId   get  set           Required      public virtual string Secret   get  set              public virtual List lt User gt  Users   get  set        public virtual List lt Post gt  Posts   get  set                public virtual ApplicationUser Admin   get  set       public class Post        Key       DatabaseGenerated DatabaseGeneratedOption Identity       public virtual int PostId   get  set        public virtual string Content   get  set        public virtual string Link   get  set        public virtual string Image   get  set        public virtual bool IsSpecial   get  set           Required      public virtual App App   get  set           Required      public virtual DateTime  PublishDate   get  set       public class User        Key       DatabaseGenerated DatabaseGeneratedOption Identity       public virtual int UserId   get  set          MaxLength 500       public virtual string FacebookId   get  set          MaxLength 500       public virtual string Token   get  set            Required      public virtual App App   get  set        Here are my IdentityModels   public class ApplicationUser   IdentityUser       public virtual List lt App gt  Apps   get  set        public bool  IsPremium   get  set         DataType DataType Date       public DateTime  LastPublishDateTime   get  set       public class ApplicationDbContext   IdentityDbContext lt ApplicationUser gt        public ApplicationDbContext             base  dCon                   protected override void OnModelCreating DbModelBuilder modelBuilder                base OnModelCreating modelBuilder           modelBuilder Entity lt IdentityUser gt    ToTable  Admins            modelBuilder Entity lt ApplicationUser gt    ToTable  Admins            modelBuilder Entity lt IdentityUserRole gt    ToTable  AdminRoles            modelBuilder Entity lt IdentityUserLogin gt    ToTable  Logins            modelBuilder Entity lt IdentityUserClaim gt    ToTable  Claims            modelBuilder Entity lt IdentityRole gt    ToTable  Roles

User · Answer

This can happen when you change the data annotation of a model property. for example: adding [Required] to a property will cause a pending change in the database design.

The safest solution is to run on the Package Manager Console:

add-migration myMirgrationName

which will display the exact changes in the Up() method. Therefore, you can decide if you really want to apply such changes via the:

update-database

Otherwise, you may just delete the latest migration from the __MigrationHistory table and from the Migrations folder the Solution Explorer.

User · Answer

I know I am very late  but I want to give contribution too  This error is really strange  because the browser is not able to understand how the changes should be rendered because the classes and their properties might have changed but not committed to the database    So do one thing   create one migration in Package Manager Console Tools   NuGet Package Manager   Package Manager Console  using this command      add-migration UpdateMigration   where UpdateMigration is the name of your Migration  You can give it any name of your choice but please be specific   After that  we just need to update the database  so run this      update-database   Now that you have committed your changes to the database  just refresh your browser and there you go   Hope this helps

User · Answer

Deleting Rows in    MigrationHistory  table with Older productVersion worked for me  This answer is for those who don t want to delete entire    MigrationHistory  table  Just delete the rows with older version in ProductVersion Column  Hope it helps some one

User · Answer

remove all tables identity  Delete  MigrationHistory Delete AspNetRoles Delete AspNetUserClaims Delete AspNetUserLogins Delete AspNetRoles Delete AspNetUser

User · Answer

simply the error means that your models has changes and is not in Sync with DB  so go to package manager console   add-migration foo2 this will give a hint of what is causing the issue   may be you removed something or in my case I remove a data annotation   from there you can get the change and hopefully reverse it in your model   after that delete foo2

User · Answer

Below was the similar kind of error i encountered  The model backing the  PsnlContext  context has changed since the database was created  Consider using Code First Migrations to update the database  http   go microsoft com fwlink  LinkId 238269    I added the below section in the Application Start event of the Global asax to solve the error  Database SetInitializer  null    This fixed the issue

User · Answer

It was such a strange error   It wasn t my error at the end  it was Microsoft s   I installed the Entity framework the   pre-release  version and it was responsible for this error   when i upgraded to the stable release it disapperared   thank you everyone believe me when i asked this question i searched like for a week or so for its solution so i am pretty sure that this problem isn t anywhere else   the version of entity framework dll that caused the problem was 6 0 2 if it helps

User · Answer

Just Delete the migration History in  MigrationHistory in your DataBase  It worked for me

User · Answer

If you delete the     MigrationHistory   table from your  database   System Tables  then it will work

User · Answer

Just in case anyone else stumbles upon this that was doing a database first implementation like me   I made a change by extending the ApplicationUser class  adding a new field to the AspNetUsers table  and then had this error on startup   I was able to resolve this by deleting the record created in the   MigrationHistory table  there was only one record there  I assume EF decided that I needed to update my database using the migration tool - but I had already done this manually myself

User · Answer

Everybody getting a headache from this error  Make absolutely sure all your projetcs have a reference to the same Entity Framework assembly   Short story long   My model and my application were in different assemblies  These assemblies were referencing a different version of Entity framework  I guess that the two versions generated a different id for the same modell  So when my application ran the id of the model didn t match the one of the latest migration in   MigrationHistory  After updating all references to the latest EF release the error never showed up again

User · Answer

From the Tools menu  click NuGet Package Manger  then click Package Manager Console  PMC   Enter the following commands in the PMC   Enable-Migrations Add-Migration Init Update-Database Run the application  The solution to the problem is from here

User · Answer

I was having same problem as a7madx7  but with stable release of EF  v6 1 1   and found resolution posted in   http   cybarlab com context-has-changed-since-the-database-was-created  with variation in  http   patrickdesjardins com blog the-model-backing-the-context-has-changed-since-the-database-was-created-ef4-3  2nd link includes specific mention for VB       you can simply add all the databasecontext that are having this problem on your app start method in the global asax file like this    Database SetInitializer Of DatabaseContext  Nothing    NB  i had to replace  DatabaseContext  with the name of my class implementing DbContext  Update  Also  when using codefirst approach to connect to existing tables  check database to see if EF has created a table   migrationhistory  to store mappings  I re-named this table then was able to remove SetInitializer from global asax

User · Answer

This post fixed my issue  It s all about adding the following line in Application Start   in Global asax    Database SetInitializer lt Models YourDbContext gt  null    However it cause database recreation for every edit in your model and you may loose your data

User · Answer

I just solved a similar problem by deleting all files in the website folder and then republished it

User · Answer

I spent many days to solve this issue  analyzed many different posts and tried many options and finally fixed   This 2 projects in my solution using EF code first migrations    Console Application  DataModel  that mainly using as assembly which contains all my code first entities  DbContext  Mirgations and generic repository  I have included to this project separate empty local database file  in DataModel App Data folder  to be able generate migrations from Package Manager Console     WebApi  which references to DataModel project and uses local database file from WebApi App Data folder  that not included in project   I got this error when requested WebApi     My environment    Windows 8 1 x64 Visual Studio 2015 Professional with Update 1 all my projects targeted for  NET Framework 4 6 1 EntityFramework 6 1 3 from NuGet   Here I collected all the remarks you should pay attention and all conditions requirements which must be met  to avoid mentioned exception     You should use only one version of EntityFramework Nuget package for all projects in your solution  Database  created by running sequentially all migration scripts should have the same structure schema as you target database and correspond to entity model  Following 3 things must exactly correspond reflect match each other    Your all migration script up to last Current code first entity model state  DbContext  entities  Target database  Target database  mdf file  should be updated correspond up to last migration script  Verify that    MigrationHistory  table in your target database contains records for all migration scripts that you have  it means that all migration scripts was successfully applied to that database  I recommend you to use Visual Studio for generation correct code first entities and context that corresponds to your database  Project -  Add New Item -  ADO NET Entity Data Model -  Code First from database    Of course  as an alternative  if you have no database you can write manually model  code first entities and context  and then generate initial migration and database   Name of connection string e g  MyConnectionString in config file of startup project  Web config App config     lt configuration gt     lt connectionStrings gt       lt add name  MyConnectionString  connectionString       gt     lt  connectionStrings gt   lt configuration gt    should be equal to parameter passed in constructor of your DbContext    public partial class MyDbContext   DbContext        public MyDbContext            base  name MyConnectionString              Before using Package Manager Console  make sure that you are using correct database for update or generate migration and needed project is set as startup project of solution  For connect to database it will use connection string from that  config file  which in project  that is set as startup project   And the main  which fixed my issue  It is weird  but in my WebApi bin folder DataModel exe was old  not refreshed since last build  Since migrations was embedded in my assembly DataModel exe then my WebApi updated database using old mirgations  I was confused why after updating database in WebApi it not corresponds to latest migration script from DataModel  Following code automatically creates if not exists  or updates to latest migration local database in my WebApi App Data folder       public class WebApiApplication   System Web HttpApplication             protected void Application Start                       Database SetInitializer new MigrateDatabaseToLatestVersion lt ODS DbContext  Configuration gt                        I tried clean and rebuild solution but it did not help  than I completely removed bin and obj folders from WebApi  deleted database files from WebApi App Data  built  restarted WebApi  made request to it  it created correct database - lazy initialization  using lines above   which corresponds to latest migration and exception didn t appear more  So  this may fix your problem    remove manually bin  obj folders from your startup project  which generates updates your database  build your startup project or better clean and rebuild all you solution  recreate database by starting project  will execute lines above  or use Package Manager Console  update-database  command   manually check whether generated db and   MirgationHistory corresponds to latest migration script

User · Answer

When I am developing  I prefer to use this practical class to configure Migrations   Hope it helps   public class ApplicationDbContext   IdentityDbContext lt ApplicationUser gt        public ApplicationDbContext             base  DefaultConnection   throwIfV1Schema  false                this Configuration LazyLoadingEnabled   false             public static ApplicationDbContext Create                 return new ApplicationDbContext               protected override void OnModelCreating DbModelBuilder modelBuilder                base OnModelCreating modelBuilder            modelBuilder Conventions Remove lt OneToManyCascadeDeleteConvention gt             modelBuilder Conventions Remove lt ManyToManyCascadeDeleteConvention gt              Database SetInitializer new StackOverflowInitializer                public class StackOverflowInitializer   DropCreateDatabaseIfModelChanges lt ApplicationDbContext gt                public StackOverflowInitializer                            TODO NOTHING  COMMENT ALL                 IF CHANGES  RECREATE             Database SetInitializer new DropCreateDatabaseIfModelChanges lt ApplicationDbContext gt                      CREATE ONLY NOT EXITS               Database SetInitializer lt Context gt  new CreateDatabaseIfNotExists lt ApplicationDbContext gt                            public System Data Entity DbSet lt stackoverflow Models Company gt  Companies   get  set

User · Answer

This worked for me - no other changes required   DELETE FROM  dbo     MigrationHistory

User · Answer

Delete existing db  create new db with same name   copy all data   it will work

User · Answer

this comes because you add some property to one of your model and you did not update-Database   to solve this you have to remove it from model or you have to add-migration anyProperName  with that properties and Update-database

User · Answer

This error occurred to me when I made changes to my Model and did not make migration for the changes to update the database    If you have ever made changes to your model in Code First Migration Schema  Don t forget to add migration  add-migration UpdatesToModelProperites    The above command will read all the changes you have made in the model and will write it in the Up   and Down   methods    Then simply update your database using the below command    update-database   This what worked for me

[.net] The model backing the 'ApplicationDbContext' context has changed since the database was created

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