Question

My entity classes need to also comprise logic.

What will entity framework code-first mapper do, when an entity with a method is encountered?

Will it just ignore and map only properties to a database?

Side question:
Is it a good practice to have a logic in an entity classes at all?

Answer 1

Methods in your entities will be ignored when EF performs the model discovery. You can even add extra properties and mark them as not mapped.

public class Foo
{
     public int Id { get; set; } 

     public Bar Bar { get; set; }

     public string Baz { get; set; }

     public ValidationResult Validate(ValidationContext context)
     {
     }
}

public class MyContext : DbContext
{
    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
         modelBuilder.Entity<Foo>().Ignore(f => f.Baz);

         modelBuilder.Ignore<Bar>();
    }
}

Here Bar, ValidationResult, ValidationContext will not be part of the model and Baz property will not be mapped to a column.

Its perfectly OK to have logic in your entity classes.