EF 4.1 - How to add a default on insertion for datetime column

Question

Using EF 4.1 how could I add a default value to the underlying table? In this particular case how could I set a datetime column to the equivalent of getdate every time I insert a new record to the database, without having to set it in code.

Thanks in advance

Answer 1

The solution proposed by @elkdanger is way to go but just if you use code-first approach you don't have to create partial class - you can place initialization directly to your entity.

Don't use database approach! It will not work because it would demand marking property as database generated (to be correctly repopulated after insert). Once you mark property database generated you can never change its value in the application.

The last option is overriding SaveChanges in your derived DbContext and setting the property manually. Something like:

public override int SaveChanges()
{
    var entities = ChangeTracker.Entries<YourEntityType>()
                                .Where(e => e.State == EntityState.Added)
                                .Select(e => e.Entity);
    var currentDate = DateTime.Now;
    foreach(var entity in entities)
    {
        entity.Date = currentDate;
    }

    return base.SaveChanges();
}

This approach can be better if there can be significant difference between creating an instance of the entity and saving the instanance.

Answer 2

You could create a partial class for your entity, and inside the constructor set the date column to DateTime.Now. This way, every time you create an instance of your class, that field will be set to the current date "automatically".