Entity Framework code-first migration fails with update-database forces unneccessary add-migration

Question

I have a funny effect using migration  EF 5 0  and code-first   I created some models with GUID primary keys   BTW  It is important for me  that SQL Server uses NEWSEQUENTIALID    which seems to be the default value in the current version   At some point I activated migrations  I added some code to the initial migration  this is mostly  Index   as needed   When I delete the database and call update-database  I get the following error      Unable to update database to match the current model because there   are pending changes and automatic migration is disabled  Either write   the pending model changes to a code-based migration or enable   automatic migration  Set   DbMigrationsConfiguration AutomaticMigrationsEnabled to true to enable   automatic migration  You can use the Add-Migration command to write   the pending model changes to a code-based migration    I tried AutomaticMigrationsEnabled   true  which worked without changing or adding anything   But since I don t want AutomaticMigrationsEnabled  I also tried deleting the database again  called update-database and then add-migration  I ended up with an additional migration that seems not to change anything  see below   I also tried adding these lines to the bottom of the initial migration - but this does not change anything   One of the models    Table Speaker TABLENAME   public class Speaker   BaseModel       public const String TABLENAME    Speaker         Key  DatabaseGenerated DatabaseGeneratedOption Identity       public Guid Id   get  set          Required       MaxLength 50  ErrorMessage    Name must be 50 characters or less        public string Name   get  set        The initial migration code   public partial class InitialCreate   DbMigration       public override void Up                                  CreateTable               dbo Speaker               c   gt  new                                       Id   c Guid nullable  false  identity  true                       Name   c String nullable  false  maxLength  50                                   PrimaryKey t   gt  t Id               Index t   gt  t Name  true  false        added manually  unique Name                           internal sealed class Configuration   DbMigrationsConfiguration lt MyProject Repositories DBContext gt        public Configuration                 AutomaticMigrationsEnabled   false             protected override void Seed MyProject Repositories DBContext context                                 Below is the code created by add-migration  It does not seem to do anything new - maybe I am missing something   public partial class UnneccessaryMigration   DbMigration       public override void Up                    isn t this the exact same code from InitialMigrations          AlterColumn  dbo Speaker    Id   c   gt  c Guid nullable  false  identity  true                              public override void Down                               AlterColumn  dbo Speaker    Id   c   gt  c Guid nullable  false              So I am curious  What did I do to disorientate migrations  And what can I do to get it working with just one initial migration   Solution  The following workaround did it for me    I deleted the database and all migrations as decribed here  https   stackoverflow com a 11679386 3168401 Executed Enable-Migrations   Add-Migration Initial Merged my handmade  Index   changes into the file  Now Update-Database works again - also repeatedly  when deleting the database

User · Answer

In answer to your general question of

So I am curious: What did I do to disorientate migrations? And what can I do to get it working with just one initial migration?

I've just had the same error message as you after I merged several branches and the migrations got confused about the current state of the database. Worst of all, this was only happening on the client's server, not on our development systems.

In trying to work out what was happening there, I came across this superb Microsoft guide:

Microsoft's guide to Code First Migrations in Team Environments

Whilst that guide was written to explain migrations in teams, it also gives the best explanation I've found of how the migrations work internally, which may well lead to an explanation for the behaviour your seeing. It's very worth putting an hour aside to read all of that for anyone who works with EF6 or below.

For anyone brought to this question by that error message after merging migrations, the trick of generating a blank migration with the current state of the database solved things for me, but do be very sure to have read the whole guide to know if that solution is appropriate in your case.

User · Answer

I had this problem and the suggestions above didn t help  What I found is that the add-migration reads the current state and creates a signature of the current model  You must modify your model before modifying  So the sequence is    Modify model run add-migration   I did the opposite and added the migration before modifying my model  which was empty  so I added the new columns  and then ran my code   Hope this helps

User · Answer

if you set your context model as code first based on exist database so  you have to for set migration   Add-Migration InitialCreate    IgnoreChanges Update-database -force   and then change your context model and set   Add-migration RemoveIspositive Update-database -force

User · Answer

I understand this is a very old thread  However  wanted to share how I encountered the message in my scenario and in case it might help others  I created an Add-Migration  lt Migration name gt  on my local machine  Didn t run the update-database yet  Meanwhile  there were series of commits in parent branch that I must down merge  The merge also had a migration to it and when I fixed conflicts  I ended up having 2 migrations that are added to my project but are not executed via update-database  Now I don t use enable-migrations -force in my application  Rather my preferred way is execute the update-database -script command to control the target migrations I need  So  when I attempted the above command  I get the error in question   My solution was to run update-database -Script -TargetMigration  lt migration name from merge gt  and then my update-database -Script -TargetMigration  lt migration name gt  which generated 2 scripts that I was able to run manually on my local db  Needless to say above experience is on my local machine

User · Answer

Try this   PM gt  Enable-migrations -force PM gt  Add-migration MigrationName PM gt  Update-database -force

User · Answer

Entity Framework does have some issues around identity fields   You can t add GUID identity on existing table  Migrations  does not detect changes to DatabaseGeneratedOption  Reverse engineering does not mark GUID keys with default NEWSEQUENTIALID   as store generated identities  None of these describes your issue exactly and the Down   method in your extra migration is interesting because it appears to be attempting to remove IDENTITY from the column when your CREATE TABLE in the initial migration appears to set it    Furthermore  if you use Update-Database -Script or Update-Database -Verbose to view the sql that is run from these AlterColumn methods you will see that the sql is identical in Up and Down  and actually does nothing  IDENTITY remains unchanged  for the current version - EF 6 0 2 and below  - as described in the first 2 issues I linked to   I think you should delete the redundant code in your extra migration and live with an empty migration for now  And you could subscribe to vote for the issues to be addressed    References   Change IDENTITY option does diddly squat  Switch Identity On Off With A Custom Migration Operation

User · Answer

for me i solved it like the following  In Visual Studio 2015   From View menu click Other Windows then click Package Manager Console  then run the following commands    PM gt  enable-migrations   Migrations have already been enabled in project  mvcproject   To overwrite the existing migrations configuration  use the -Force parameter   PM gt  enable-migrations -Force   Checking if the context targets an existing database    Code First Migrations enabled for project mvcproject   then add the migration name under the migration folder it will add the class you need in Solution Explorer by run the following command  PM gt Add-migration AddColumnUser   Finally update the database   PM gt  update-database

User · Answer

When using VS2019  MVC5 - look under Migrations folder for file Configuration cs  Edit   AutomaticMigrationsEnabled   true    -

User · Answer

I also tried deleting the database again  called update-database and   then add-migration  I ended up with an additional migration that seems   not to change anything  see below    Based on above details  I think you have done last thing first  If you run Update database before Add-migration  it won t update the database with your migration schemas  First you need to add the migration and then run update command   Try them in this order using package manager console   PM gt  Enable-migrations   You don t need this as you have already done it PM gt  Add-migration Give it a name PM gt  Update-database

[c#] Entity Framework code-first: migration fails with update-database, forces unneccessary(?) add-migration

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