Code-first Entity Framework dropping and recreating a table when model hasn't changed

Question

I have the following class (inheriting from BaseEntity which just has an int Id property):

public class User : BaseEntity
{
    public string Email { get; set; }
    public string FirstName { get; set; }
    public string LastName { get; set; }
    public DateTime Created { get; set; }
    public DateTime? LastLogon { get; set; }
    public string LastIpAddress { get; set; }
    public string Password { get; set; }        
    public string CustomData { get; set; }
    public int FailedLogInAttempts { get; set; }
    public bool LockedOut { get; set; }
    public UserRole Role { get; set; }
}

It is mapped by the following class:

public class UserMap : EntityTypeConfiguration<User>
{
    public UserMap()
    {
        HasKey(t => t.Id);
        Property(t => t.Created);
        Property(t => t.CustomData);
        Property(t => t.Email);
        Property(t => t.FailedLogInAttempts);
        Property(t => t.FirstName);
        Property(t => t.LastIpAddress);            
        Property(t => t.LastLogon).IsOptional();
        Property(t => t.LastName);
        Property(t => t.LockedOut);
        Property(t => t.Password);            
    }
}

Now on occasion when I run the project I find that the table is dropped and recreated. I can tell this because I have seen the table disappear and reappear in SQL Server (by repeatedly spamming a select query on the table for want of a better method!).

I have a custom onModelCreating as I am pulling mappings from external DLLs as well (the user is not from an external DLL). The code for my custom onModelCreating is:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    var typesToRegister = AppDomain.CurrentDomain.GetAssemblies().SelectMany(a => a.GetTypes())
    .Where(type => !String.IsNullOrEmpty(type.Namespace))
    .Where(type => type.BaseType != null && type.BaseType.IsGenericType && type.BaseType.GetGenericTypeDefinition() == typeof(EntityTypeConfiguration<>));

    foreach (var type in typesToRegister)
    {
        dynamic configurationInstance = Activator.CreateInstance(type);
        modelBuilder.Configurations.Add(configurationInstance);
    }

    Database.SetInitializer<DataContext>(new MigrateDatabaseToLatestVersion<DataContext, Migrations.Configuration>());            
    base.OnModelCreating(modelBuilder);
}

I have also customised my migration config with the following so that migrations are automatic:

public Configuration()
{           
    AutomaticMigrationsEnabled = true;     
}

I am sure it's down to me doing something stupid but as it doesn't happen every time I clean => rebuild => run the project I am finding it very hard to track down the problem.

To recap:

• I have a model that has not changed (Including namespaces etc, properties types of the model from classes I have created etc.)
• Sometimes when I run the project the table this model relates to is dropped and recreated.

I would appreciate if anyone could help me track down where I can begin to look for the root cause of the problem. If you require me to post anymore of my code please let me know.

Thanks.

Answer 1

You can change

AutomaticMigrationsEnabled = false;

and then, update your model only when you make changes on it using the console pointing to to your entity project:

add-migration [Migrator_Name]
update-database