Entity Framework “Code First + Computed GETDATE()”

Need to setup a “Created” DateTime field in your SQL table that is auto-computed to add the current date and time that the field is inserted into the database? 

If you’re doing so in SQL – in the “Default Value or Binding” you just need to enter GETDATE() or GETUTCDATE() – insert a record, and you’ll see the date/time value automatically added to that column.  “…that was easy…”

But how to do the same thing when using Entity Framework Code First?

No big deal here either – as long as you add the couple lines of code described here…

First, we need to add the “DatabaseGenerated” DataAnnotation that describes the “Created” field as a computed field.  See Code First DataAnnotation’s for more…
 

public class DemoRecord

{

    public long Id { get; set; }

    public string Name { get; set; }

    [DatabaseGenerated(DatabaseGeneratedOption.Computed)]

    public DateTime? Created { get; set; }

}

Then as we discussed in my earlier Code First blog posts (Entity Framework “Code First + Migration” 101 and Entity Framework “Code First + Existing Database” 102) – in the “Package Manager Console” window type “Add-Migration AddedComputedColumn” – where “AddedComputedColumn” could be any name you want to give this update — and then in the “Migrations” folder open the newly created migration script matching the name you gave it, for example, “201309021659377_AddedComputedColumn.cs” – commenting out what you see in line 5, with the updated command in line 6.
 

public partial class AddedComputedColumn : DbMigration

{

    public override void Up()

    {

        //AddColumn("dbo.DemoRecords", "Created", c => c.DateTime());

        AddColumn("dbo.DemoRecords", "Created", c => c.DateTime(defaultValueSql: "GETDATE()"));

    }

    public override void Down()

    {

        DropColumn("dbo.DemoRecords", "Created");

    }

}

And simple as that, in the “Package Manager Console” when you type “Update-Database” – you now have a auto-computed date/time field…  Rock on…