Invalid migration - this is not really what we wanted...

InvalidMigration.cs

protected override void Up(MigrationBuilder migrationBuilder)
{
    migrationBuilder.DropTable(
        name: "Cows");

    migrationBuilder.DropPrimaryKey(
        name: "PK_Horses",
        table: "Horses");

    migrationBuilder.DropColumn(
        name: "Id",
        table: "Horses");

    migrationBuilder.RenameTable(
        name: "Horses",
        newName: "Animal");

    migrationBuilder.AlterColumn<int>(
        name: "MaxJumpHeight",
        table: "Animal",
        nullable: true,
        oldClrType: typeof(int));

    migrationBuilder.AddColumn<int>(
        name: "Number",
        table: "Animal",
        nullable: false,
        defaultValue: 0);

    migrationBuilder.AddColumn<int>(
        name: "Year",
        table: "Animal",
        nullable: false,
        defaultValue: 0);

    migrationBuilder.AddColumn<string>(
        name: "Discriminator",
        table: "Animal",
        nullable: false,
        defaultValue: "");

    migrationBuilder.AddColumn<int>(
        name: "Weight",
        table: "Animal",
        nullable: true);

    migrationBuilder.AddPrimaryKey(
        name: "PK_Animal",
        table: "Animal",
        columns: new[] { "Number", "Year" });
}