Oracle Entity Framework provider doesn't store DateTime.Now with milliseconds

Aha! My awesome colleague had an idea and it worked!

In our EF code we tried putting

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    modelBuilder.Entity<EntityClass>().Property(p => p.TIMESTAMP).HasPrecision(6);
}

And then the DateTime.Now with milliseconds got stored into the database

Update - it's worth mentioning how I got in this predicament

Building the Database with Model First in a "test" application

1. My app has to work with both SQL Server and Oracle. So...
2. I started by designing my database in an EDMX Diagram
3. Once the diagram was done, I generated the DDL for SQL Server.

4. For some reason the Oracle EF provider couldn't generate the DDL so I proceeded to manually make changes to the SQL Server DDL so it would be correct syntactically

   1st Problem - my Oracle DDL was using a Date instead of Timestamp. Make sure you use Timestamp!!! DateTime in Oracle doesn't store milliseconds.

Using Code First from Database for the actual solution

1. I wanted the app to use the Code First approach (Just my preference. I think it's easier to maintain)
2. So I connected to the SQL Server database and generated all of my classes from that schema.
3. I got all of my unit tests passing and then decided to test it with the Oracle database
4. Even after changing from DATE to Timestamp, I was still having problems with the milliseconds going in.
5. I generated another Code First model in a test visual studio solution with a TIMESTAMP(6) type in Oracle, except when I looked at the OnModelCreating code, it did not generate anything with HasPrecision(6) nor were there any decorators on the property in the generated C# POCO class.
6. I noticed if you have the HasPrecision(6) code in your OnModelCreating, the Code FirstCreateDatabase() will actually make an Oracle TIMESTAMP(6). If you don't, then the Oracle EF provider will use DATE

I think if you do the Model First approach you can set precision values in the EDMX diagram, but I've heard that it's bad practice.

Another possible solution is to set precision in the configuration class. If you have an Entity like this:

public class MyEntity
    {
        public DateTime? MyDateTimeWithPrecision{ get; set; }
    }

If you use configuration to be added on model builder as following:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
         modelBuilder.Configurations.Add(new MyEntityConfiguration());
        }

then in your configuration class you can do as following:

class MyEntityConfiguration : EntityTypeConfiguration<MyEntity>
    {
        public MyEntityConfiguration()
        {
            Property(e => e.MyDateTimeWithPrecision)
                .HasPrecision(6);
         }
     }

With this architectural solution you can have a MyEntityConfiguration class for each entity of your model, so your code should be more readable.