Update Database after Model Changes - Entity Framework 7

Question

I have created an app using the lastest ASP.NET5 MVC 6 Entity Framework 7 and setup migrations using

dnx . ef migration add Initial
dnx . ef migration apply

This works but when I make a change to the model the database is not updated. I would like to have the database automatically update after a model change when I run the program.

My research only points me to old information that doesn't seem to be appropriate to Entity Framework 7.

My current code:

 public ApplicationDbContext(): base()
   {

        if (!_created)
        {

             Database.AsRelational().ApplyMigrations();
             _created = true;         
        }
  }

Can someone point me in the right direction?

I believe it use to work something like this:

Database.SetInitializer(new DropCreateDatabaseAlways<MyContext>());

You must manually run migrations with EF7, or call ApplyMigrations from code, there is nothing autpmagic in EF7 — ErikEJ
– ErikEJ, Commented Jul 4, 2015 at 6:43
Hey @ErikEJ I am calling applymigrations (updated my question) it doesnt seem to do anything... What exactly is it suppose to do? I cant find any documentation. I don't understand why it cant be automatic, it use to be. See link. Could you please elaborate on your comment? — Reafidy
– Reafidy, Commented Jul 4, 2015 at 7:20
I just thought there would be a way to automate it, at worst I can do Database.EnsureDeleted(); if (Database.EnsureCreated()) { // Database.AsRelational().ApplyMigrations(); _created = true; } but that deletes my test data every time. — Reafidy
– Reafidy, Commented Jul 4, 2015 at 8:11

ErikEJ · Accepted Answer · 2016-02-16 08:16:27Z

6

You must manually run migrations with EF7 from command line, or call Database.Migrate from code, there is nothing automagic in EF7 (a deliberate decision) and after you change your model, create a new migration

edited Feb 16, 2016 at 8:16

answered Jul 4, 2015 at 8:48

ErikEJ

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6 Comments

Reafidy Over a year ago

Thanks, It seems like a step backwards to me. This use to be possible via code. Now every time I change the model (very frequent) I have to delete the old migration, fire up power shell create a new migration, go to sql server studio delete the database and then back to power shell to apply the new database schema.

Reafidy Over a year ago

And ApplyMigrations as you suggest does not work, can you remove that from your answer, if that worked I wouldn't need to do it manually as above.

ErikEJ Over a year ago

Only call ApplyMigrations once during app startup - and what does "does not Work" mean?

Reafidy Over a year ago

Sorry i should have said applymigrations is not an answer to the problem. Applymigrations i run at startup but it only seems to build the initial database once. If i then change the model. Applymigrations does nothing, it does not apply the changes to the database as i expceted.

Reafidy Over a year ago

When you are talking about ApplyMigrations as an alternative to manually running migrations in your answer, it suggests ApplyMigrations is an automatic solution but in fact it only seems to work once and it does not apply changes to the model which is my question.

|

retsvek · Accepted Answer · 2016-02-15 22:35:17Z

There appears to be some confusion between the creation of migrations and the process of updating the database structure.

In EF7, you can no longer automatically generate the migration (the delta between the current database structure and the entity definitions). That HAS to be done at the command line using the "migrations add" command.

Updating the structure of the database, however, can still be done via code. That is done using the dbContext.Database.Migrate() method. You can wire this up in your Startup so that when your app first boots it will ensure your database has been brought up to date with the now-current version of your app.

So your development workflow can be:

modify entity definitions
run "migrations add" command
launch your app*
- number 3 above assumes you've wired up the Migrate() call mentioned above in your Startup. Otherwise you also have to execute the "database update" command manually.

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