Brtdku

I am trying to use Code-First EF6 with default SQL values.

For example, I have a "CreatedDate" column/property not null with a default in SQL of "getdate()"

How do I represent this in my code Model? Currently I have:

<DatabaseGenerated(DatabaseGeneratedOption.Computed)>

Public Property CreatedDate As DateTime

Will this work, or will I need to use a nullable even though the actual column should be not null, so EF doesn't send a value when it hasn't been set:

<DatabaseGenerated(DatabaseGeneratedOption.Computed)>

Public Property CreatedDate As DateTime?

Or is there a better solution out there?

I don't want EF to handle my defaults - I know this is available to me but not possible in my current situation.

Currently in EF6 there is not an attribute to define database functions used for a certain property default value. You can vote on Codeplex to get it implemented:

https://entityframework.codeplex.com/workitem/44

The accepted way to implement something like that is to use Computed properties with Migrations where you specify the default database function.

Your class could look like this in C#:

public class MyEntity

{

    [Key]

    public int Id { get; set; }

    public string Name { get; set; }



    [DatabaseGenerated(DatabaseGeneratedOption.Computed)]

    public DateTime Created { get; set; }

}

The computed property doesn't have to be nullable.

Then you have to run a migration and modify it by hand to include the default SQL function. A migration could look like:

public partial class Initial : DbMigration

{

    public override void Up()

    {

        CreateTable(

            "dbo.MyEntities",

            c => new

                {

                    Id = c.Int(nullable: false, identity: true),

                    Name = c.String(),

                    Created = c.DateTime(nullable: false, defaultValueSql: "GetDate()"),

                })

            .PrimaryKey(t => t.Id);



    }



    public override void Down()

    {

        DropTable("dbo.MyEntities");

    }

}

You will notice the defaultValueSql function. That is the key to get the computation working

Accepted answer is correct for EF6, I'm only adding EF Core solution; (also my solution focuses on changing the default-value, rather than creating it properly the first time)

There is still no Data-Attribute in EF Core.

And you must still use the Fluent API; it does have a HasDefaultValue

protected override void OnModelCreating(ModelBuilder modelBuilder)

{

    modelBuilder.Entity<Blog>()

        .Property(b => b.Rating)

        .HasDefaultValue(3);

}

Note, there is also HasDefaultValueSql for NULL case:

        .HasDefaultValueSql("NULL");

And you can also use the Migrations Up and Down methods, you can alter the defaultValue or defaultValueSql but you may need to drop Indexes first. Here's an example:

public partial class RemovingDefaultToZeroPlantIdManualChange : Migration

{

    protected override void Up(MigrationBuilder migrationBuilder)

    {

        migrationBuilder.DropIndex(

            name: "IX_TABLE_NAME_COLUMN_NAME",

            table: "TABLE_NAME"

        );



        migrationBuilder.AlterColumn<int>(

            name: "COLUMN_NAME",

            table: "TABLE_NAME",

            nullable: true,

            //note here, in the Up method, I'm specifying a new defaultValue:

            defaultValueSql: "NULL",

            oldClrType: typeof(int));



        migrationBuilder.CreateIndex(

            name: "IX_TABLE_NAME_COLUMN_NAME",

            table: "TABLE_NAME",

            column: "COLUMN_NAME"

        );

    }



    protected override void Down(MigrationBuilder migrationBuilder)

    {

        migrationBuilder.DropIndex(

            name: "IX_TABLE_NAME_COLUMN_NAME",

            table: "TABLE_NAME"

        );



        migrationBuilder.AlterColumn<int>(

            name: "COLUMN_NAME",

            table: "TABLE_NAME",

            nullable: true,

            //note here, in the Down method, I'll restore to the old defaultValue:

            defaultValueSql: "0",

            oldClrType: typeof(int));



        migrationBuilder.CreateIndex(

            name: "IX_TABLE_NAME_COLUMN_NAME",

            table: "TABLE_NAME",

            column: "COLUMN_NAME"

        );





    }

}