Required and StringLength are ignored by ASP.NET MVC5 - EF6 - asp.net

Question

I am using Visual Studio 2017 with a asp.net mvc 5 and entity framework 6. I am following an online course and the steps the author is doing, is creating 2 classes with properties, then marking properties as [Required] and assign [StringLength(255)] to some other string properties. The modifications work on one class but not on the other.
This is the code for the 2 classes:
The one that's working:
public class Genre
{
public byte Id { get; set; }
[Required]
[StringLength(255)]
public string Name { get; set; }
}
The one that's not working:
public class Gig
{
public int Id { get; set; }
[Required]
public ApplicationUser Artist { get; set; }
public DateTime DateTime { get; set; }
[Required]
[StringLength(255)]
public string Venue { get; set; }
[Required]
public Genre Genre { get; set; }
}
I ran migration first time before adding the attributes, and the CreateTables.cs migration looks like this:
public override void Up()
{
CreateTable(
"dbo.Genres",
c => new
{
Id = c.Byte(nullable: false),
Name = c.String(),
})
.PrimaryKey(t => t.Id);
CreateTable(
"dbo.Gigs",
c => new
{
Id = c.Int(nullable: false, identity: true),
DateTime = c.DateTime(nullable: false),
Venue = c.String(),
Artist_Id = c.String(maxLength: 128),
Genre_Id = c.Byte(),
})
.PrimaryKey(t => t.Id)
.ForeignKey("dbo.AspNetUsers", t => t.Artist_Id)
.ForeignKey("dbo.Genres", t => t.Genre_Id)
.Index(t => t.Artist_Id)
.Index(t => t.Genre_Id);
}
Then I added the attributes to my code, and added a new migration, When I run add migration, the generated code in the migration is like this:
public override void Up()
{
DropForeignKey("dbo.Gigs", "Artist_Id", "dbo.AspNetUsers");
DropForeignKey("dbo.Gigs", "Genre_Id", "dbo.Genres");
DropIndex("dbo.Gigs", new[] { "Artist_Id" });
DropIndex("dbo.Gigs", new[] { "Genre_Id" });
AlterColumn("dbo.Genres", "Name", c => c.String(nullable: false, maxLength: 255));
AlterColumn("dbo.Gigs", "Venue", c => c.String(nullable: false, maxLength: 255));
AlterColumn("dbo.Gigs", "Artist_Id", c => c.String(nullable: false, maxLength: 128));
AlterColumn("dbo.Gigs", "Genre_Id", c => c.Byte(nullable: false));
CreateIndex("dbo.Gigs", "Artist_Id");
CreateIndex("dbo.Gigs", "Genre_Id");
AddForeignKey("dbo.Gigs", "Artist_Id", "dbo.AspNetUsers", "Id", cascadeDelete: true);
AddForeignKey("dbo.Gigs", "Genre_Id", "dbo.Genres", "Id", cascadeDelete: true);
}
However, the generated T-SQL code to create the table is like this:
CREATE TABLE [dbo].[Gigs] (
[Id] INT IDENTITY (1, 1) NOT NULL,
[DateTime] DATETIME NOT NULL,
[Venue] NVARCHAR (MAX) NULL,
[Artist_Id] NVARCHAR (128) NULL,
[Genre_Id] TINYINT NULL,
CONSTRAINT [PK_dbo.Gigs] PRIMARY KEY CLUSTERED ([Id] ASC),
CONSTRAINT [FK_dbo.Gigs_dbo.AspNetUsers_Artist_Id] FOREIGN KEY ([Artist_Id]) REFERENCES [dbo].[AspNetUsers] ([Id]),
CONSTRAINT [FK_dbo.Gigs_dbo.Genres_Genre_Id] FOREIGN KEY ([Genre_Id]) REFERENCES [dbo].[Genres] ([Id])
);
However, the generated TSQL for the other table, was right:
CREATE TABLE [dbo].[Genres] (
[Id] TINYINT NOT NULL,
[Name] NVARCHAR (255) NOT NULL,
CONSTRAINT [PK_dbo.Genres] PRIMARY KEY CLUSTERED ([Id] ASC)
);
Why the T-SQL is not reflecting the modifications by the migration for the 1st table? Knowing that I added the migration and executed update-database, and could see the changes for one table (Genre), but not the other.
Any help is appreciated.

Answer 1

I've faced the same problem, neither StringLength nor MaxLength Data Annotations didn't helped me much. It seems I'm trying to use same online course, which initially for MSVS2015, but I'm using latest MSVS2017.
What I've tried so far:
Setting length as is and the change only it in migration
Setting specific migration version with Update-Database -TargetMigration Migration
Setting all the migrations from scratch with Update-Database -TargetMigration 0 | Update-Database -Force
Recreating database (Deleting database in SQL Server Object Explorer)
And after all SQL definition still contains initial MAX constraint, as well as table definition.
Part of migration
AlterColumn("dbo.Genres", "Name", c => c.String(nullable: false, maxLength: 255));
AlterColumn("dbo.Gigs", "Venue", c => c.String(nullable: false, maxLength: 255));
AlterColumn("dbo.Gigs", "Artist_Id", c => c.String(nullable: false, maxLength: 128));
Database definition after all migrations
[Name] NVARCHAR (MAX) NULL,
...
[Venue] NVARCHAR (MAX) NULL,
[Artist_Id] NVARCHAR (128) NULL,