实体框架代码首先 - 初始代码迁移不起作用

Question

I am trying to run migrations from code. I created my models and enabled-migrations and then added initial migration, this initial migration contains all the create tables etc

public partial class Initial : DbMigration
 {
     public override void Up()
     {
        CreateTable(..........
     }

 public override void Down()
    {
           DropTable(...........
     }
}

I then tried the Update-Database command from the visual studio which works fine, creates the database and runs the initial migration.

I then delete the database from the Sql Studio. Then I run the console app that calls the Migration Manager class

// MigrationManager class

    public static bool PerformMigration(string migrationId)
    {
        bool success = false;
        try
        {
            DbMigrationsConfiguration<MyDbContext> config = new Configuration();
    ....
            DbMigrator migrator = new DbMigrator(config);
            migrator.Configuration.AutomaticMigrationsEnabled = false;
            if (string.IsNullOrEmpty(migrationId))                    
                migrator.Update(); --> fails saying pending migration
            else
                migrator.Update(migrationId);

            success = true;
        }
        catch (Exception e)
        {
            success = false;
            LastException = e.Message;
        }

        return success;
    }

The Update() fails with 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.

//Configuration.cs
internal sealed class Configuration : DbMigrationsConfiguration<MyDbContext>
{
    public Configuration()
    {
        AutomaticMigrationsEnabled = false;
    }

    protected override void Seed(WorkflowConfigurationDbContext context)
    {
        SeedData(context);
    } 
    private void SeedData(){...}    

}

public class MyDbContext : DbContext
{
    public MyDbContext()
    {            
    }        

    public DbSet....

    }

When I step through the Update() call, it goes into Configuration() constructor and MyDbContext() constructor but fails after that, it seems like its not trying the Initial migration at all.

Answer 1

Make sure the database initialization strategy is correct in your EF context's constructor, like:

 public partial class YourContext: DbContext
 {
     static YourContext()
     {
         Database.SetInitializer<YourContext>(new CreateDatabaseIfNotExists<YourContext>());
     }
 }

This is executed the first time the database is accessed.

EDIT: A second issue may be about security: does the user that is executing the migration have the required permissions?

Answer 2

Found the issue, it was incorrect namespace.

DbMigrationsConfiguration<MyDbContext> config = new Configuration();
config.MigrationsNamespace = "Correct Namespace";