EF Core 2.1。将自定义列添加到MigrationHistory表

Question

I use EF Core 2.1 Code-First.

SELECT * FROM [dbo].[__MigrationsHistory] returns table from 2 columns

• MigrationId
• ProductVersion

I am looking for a way to add one more column AppliedOn which will store the time when migration was really applied to database.

Answer 1

You could do that in SQL :

alter table [dbo].[__MigrationHistory] add AppliedOn Datetime default getdate()

When EF applies a migration to the database it inserts a row in the table __MigrationHistory . This SQL Script adds the column AppliedOn with a default value at getDate() . When a row is inserted the column will contain the current datetime of this insert.

Or, you could do the same thing with an EF Migration :

By adding to the first migration(or to a new migration):

public partial class Intial : Migration
{
    protected override void Up(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.AddColumn<DateTime>(
            name: "AppliedOnUtc",
            schema: "Conversations",
            table: "__MigrationsHistory",                
            defaultValueSql: "GETUTCDATE()"
        );
    }
     ....
}

Answer 2

There is an article from Microsoft here that indicates how to do this in a slightly more EF friendly fashion although they suggest a lot of caution as you could inadvertently break migrations.

This article only supports EF6.0 onwards which may be supported by EF Core 2.1 but I've not tried so I don't know whether it is available to you and the article is unclear on that.

I totally get why you want to do it, but you could consider a custom patch table instead and insert into it from a Configuration.cs class when you create your code first migration. Yes it's another step, yes it's not as elegant, but it might be safer from an EF standpoint.