How can I disable migration in Entity Framework 6.0

Question

I'm trying to ignore the "Automatic" migration using Entity Framework 6.0 rc1. My problem is that I don't want this feature right now and every time that my application runs I can see all entity logs trying to create all tables.

Anticipate thanks.

Evacuee

Have you tried disabling the database initializer by using Database.SetInitializer<TContext>(null)? – Swift

Late note, but the title would be more accurate if you said "disable automatic migration", as opposed to code-based migrations – Seligmann

Answer 1

Try this:

internal sealed class Configuration : DbMigrationsConfiguration<YourContext>
{
    public Configuration()
    {
        AutomaticMigrationsEnabled = false;
    }
}

UPDATE:

You can also try this:

Database.SetInitializer<YourContextType>(new CreateDatabaseIfNotExists());

Lui

Yes, now it's working. I guess I was doing something wrong. The problem was that I deleted my __migratioHistory table and all migration files. I did Database.SetInitializer(new NullDatabaseInitializer<EfContext>()); the same as Database.SetInitializer<TContext>(null) thanks guys – Evacuee

Guys, I guess I was not clear in my question. I realize that my problem was that I have an abstract base class that inherits from DbContext, called DefaultDbContext. The problem was that I did Database.SetInitializer<DefaultDbContext>(null) but the correct way is Database.SetInitializer<ConcretClassA>(null). Thanks! – Evacuee

The first answer seems to work for me. I'm using a case where I make small models with Code First for an existing DB that I'll never change. Thanks. – Comment

As soon as you have enabled the Migrations (added the Configuration class) both of this solution will not prevent running the Migrations. AutomaticMigrationsEnabled = false - disables the automatic migration database WITH NO MIGRATIONS IN THE CODE. Moreover my expectation was to avoid the migration running with the CreateDatabaseIfNotExists initializer. I expected that EF will create a database based on the model without the Migrations. But both CreateDatabaseIfNotExists and MigrateDatabaseToLatestVersion act the same way in case existing the migrations. – Gentianaceous

Please take a look at the blog: msdn.microsoft.com/en-us/en-en/magazine/dn818489.aspx – Gentianaceous

I placed the Database.SetInitializer<YourContextType>(new CreateDatabaseIfNotExists()); in an static constructor to ensure calling only once and to not be exposed outside my DLL – Flyer

Answer 2

You can put this inside your entityFramework section of the app.config:

<contexts>
  <context type="YourNamespace.YourDbContext, YourAssemblyName" disableDatabaseInitialization="true"/>
</contexts>

This msdn page tells all about the Entity Framework Configuration Section.

Enamour

This is a much better way to permanently disable the database initialization – Ruprecht

This page tells all about the Entity Framework Configuration Section: msdn.microsoft.com/en-us/data/jj556606 – Unimpeachable

what is app.config, do you mean web.config ? – Mcardle

how I determine what is YourAssemblyName ? – Mcardle

where in the configuration put this code ? into <configuration> section ? – Mcardle

App.config or Web.config, whatever you are using. 'YourAssemblyName' is the name of the assembly where you have your DbContext. You can right-click on the project and check it under the 'Application' tab. You have to put it inside your 'entityFramework' section, under 'configuration'. – Enamour

To disable the initialization, you have to set disableDatabaseInitialization to true, not false. – Enamour

In a solution I have model project and web project (set as startup project). My EF is installed on the model project... but I have entityframework section on both App.config (model project) or Web.config (web project)... why? is that correct? – Paigepaik

Answer 3

Via web.config see - https://msdn.microsoft.com/en-us/data/jj556606.aspx#Initializers

Via Code (oddly, MUCH simpler answer)

public class MyDB : DbContext
{
    public MyDB()
    {
        Database.SetInitializer<MyDB>(null);
    }
}

or in Global.asax.cs

public class MvcApplication : System.Web.HttpApplication
{
    protected void Application_Start()
    {
        // ...

        Database.SetInitializer<MyDB>(null);

        /// ...

    }
}

Delaminate

For Code First EF, this is the cleanest answer. – Roxie

Don't put it in the constructor for the DbContext – Isar

Where would you put it? Why not in the constructor? (real question, not sarcasm) – Delaminate

What is Database namespace ? – Mcardle

@AaronSherman instead of putting this in the constructor, it can be called at any point before creating MyDB, e.g. in Application_Start(). It's a static method used to configure the initializer used by Entity Framework, so it should be called before the DbContext is created. – Forwardness

@Mcardle Database is in the System.Data.Entity namespace. – Forwardness

Nulling the dbase initializer in the entity class constructor results in a much faster initial view generation as compared to setting the initializer to null after the db context is instantiated. In my app, I had 1-1/2 MINUTE delay in my first db query. Found / fixed a couple of independent associations and got down to 55 seconds. Setting the migrations initializer after instantiating the db context got the first call down to 15 seconds. Moving the nulling of the initializer to the entity class constructor reduced the first call delay to just a couple of seconds... voila! – Kiarakibble

@IdahoB: I realize I'm a couple years late to the party.. but, you mention nulling the initializer in the entity class ctor is faster than nulling it after the dbcontext is instantiated. Clarification please: Are you talking about nulling the initializer in the POCO ctor? Or in the DbContext ctor? – Amabel

Personally I find adding the SetInitializer to the static constructor of my DbContext classes the cleanest approach. – Zilla

Answer 4

If you found this question hoping for a simple answer to disable migrations because you typed "Enable-Migrations" and now things aren't working the way you expected, like not running the seed method you thought it would run, then look in the solution explorer and delete the Migrations folder. That will stop the code from looking at the migrations config to find initialization code. To get the Migrations folder back, just run "Enable-Migrations" again.

Patter

also you can run Enable-Migrations -Force – Paigepaik

Answer 5

The mistake I was making was to call Database.SetInitializer(null); too late (after the context had been initialised). The best way to ensure migrations are disabled is to make the above call for all your contexts in your application startup. I favor this approach over setting it in the app.config so I can use my container to locate my contexts and then construct a call.

var migrationsMethod = typeof(System.Data.Entity.Database).GetMethod("SetInitializer");
foreach (var contextType in allContextTypes)
{
    migrationsMethod.MakeGenericMethod(contextType).Invoke(null, new object[] { null });                            
}

Boney

Curious, how are you getting allContextTypes? – Isar

Also curious how do you query for all contexts – Coptic

Answer 6

Disabling the automatic migration can also be configured during the invoke of the enable-migrations command (which creates the Configuration class), using the EnableAutomaticMigration parameter with a value of false:

enable-migrations -EnableAutomaticMigration:$false -ContextTypeName FullyQualifiedContextName

The will create a Configuration class which sets the AutomaticMigrationsEnabled property to false, like in the answer above.

The EnableAutomaticMigration parameter of the enable-migrations command is mentioned in this article of the Entity Framework Tutorial page (however they use it with true which seems to be the default value).

Robinson

EnableAutomaticMigration today is always false by default – Paigepaik

what is the purpose of automatic migrations? it seems everyone hates them – Paigepaik

An example of this part -ContextTypeName FullyQualifiedContextName – Paigepaik

Answer 7

Try this, Add this line in your MyContext class, this will be called before your MyContext constructor is called. This will stop creating the database as well as won't add tables into a connected database. Basically this line disables the default Code-First Database Initialization strategy which basically has a default strategy as CreateDatabaseIfNotExists.

static MyContext()
{
       System.Data.Entity.Database.SetInitializer<MyContext>(null);
}

Grim