public enum CommentType
{
    Article,
    Video,
    Event
}

public class Comment
{
    public int Id { get; set; }
    public string CommentText { get; set; }
    public string User { get; set; }
    public int? TypeId { get; set; }
    public CommentType CommentType { get; set; }
}

public class Article
{
    public int Id { get; set; }
    public string Title { get; set; }
    public string Slug { get; set; }
    public string Description { get; set; }
}

public class Video
{
    public int Id { get; set; }
    public string Url { get; set; }
    public string Description { get; set; }
}

public class Event
{
    public int Id { get; set; }
    public string Name { get; set; }
    public DateTimeOffset? Start { get; set; }
    public DateTimeOffset? End { get; set; }
}

public class MyDbContext : DbContext
{
    public DbSet<Article> Articles { get; set; }
    public DbSet<Video> Videos { get; set; }
    public DbSet<Event> Events { get; set; }
    public DbSet<Comment> Comments { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder options)
        => options.UseSqlite("Data Source=polymorphic.db");
}

var articleComments = dbContext.Comments
                .Where(x => x.CommentType == CommentType.Article && x.TypeId.Value == 1);
foreach (var articleComment in articleComments)
{
    Console.WriteLine(articleComment.CommentText);
}

var article = new Article
{
    Title = "Article A",
    Slug = "article_a",
    Description = "No Description"
};
var comment = new Comment
{
    CommentText = "It's great",
    User = "Sirwan"
};
dbContext.ArticleComments.Add(new ArticleComment
{
    Article = article,
    Comment = comment
});

dbContext.SaveChanges();

var articleOne = dbContext.Articles
    .Include(article => article.ArticleComments)
    .ThenInclude(comment => comment.Comment)
    .First(article => article.Id == 1);
var article1Comments = articleOne.ArticleComments.Select(x => x.Comment);
Console.WriteLine(article1Comments.Count());

public class Comment
{
    public int Id { get; set; }
    public string CommentText { get; set; }
    public string User { get; set; }
    
    // Article
    public virtual Article Article { get; set; }
    public int? ArticleId { get; set; }
    
    // Video
    public virtual Video Video { get; set; }
    public int? VideoId { get; set; }
    
    // Event
    public virtual Event Event { get; set; }
    public int? EventId { get; set; }
}
public class Article
{
    public int Id { get; set; }
    public string Title { get; set; }
    public string Slug { get; set; }
    public string Description { get; set; }
    public virtual ICollection<Comment> Comments { get; set; }
}

public class Video
{
    public int Id { get; set; }
    public string Url { get; set; }
    public string Description { get; set; }
    public virtual ICollection<Comment> Comments { get; set; }
}

public class Event
{
    public int Id { get; set; }
    public string Name { get; set; }
    public DateTimeOffset? Start { get; set; }
    public DateTimeOffset? End { get; set; }
    public virtual ICollection<Comment> Comments { get; set; }
}

public class MyDbContext : DbContext
{
    public DbSet<Article> Articles { get; set; }
    public DbSet<Video> Videos { get; set; }
    public DbSet<Event> Events { get; set; }
    public DbSet<Comment> Comments { get; set; }
    protected override void OnConfiguring(DbContextOptionsBuilder options)
        => options.UseSqlite("Data Source=polymorphic.db");
}

USE [master]
GO

SET ANSI_NULLS ON
GO

SET QUOTED_IDENTIFIER ON
GO

SET ANSI_PADDING ON
GO

CREATE TABLE [dbo].[Logging](
 [id] [int] IDENTITY(1,1) NOT NULL,
 [LogonTime] [datetime] NULL,
 [LoginName] [nvarchar](max) NULL,
 [ClientHost] [varchar](50) NULL,
 [LoginType] [varchar](100) NULL,
 [AppName] [nvarchar](500) NULL,
 [FullLog] [xml] NULL,
CONSTRAINT [PK_IP_Log] PRIMARY KEY CLUSTERED
(
 [id] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

GO

SET ANSI_PADDING OFF
GO

ALTER TABLE [dbo].[Logging] ADD  CONSTRAINT [DF_IP_Log_LogonTime]  DEFAULT (getdate()) FOR [LogonTime]
GO

USE [master]
GO

CREATE TRIGGER LogonTrigger
ON ALL SERVER
FOR LOGON
AS
BEGIN
   DECLARE @data XML   
   SET @data = EVENTDATA()
  
   INSERT INTO [Logging]
     (
       [LoginName],
       [ClientHost],
       [LoginType],
       [AppName],
       [FullLog]
     )
   VALUES
     (
       @data.value('(/EVENT_INSTANCE/LoginName)[1]', 'nvarchar(max)'),
       @data.value('(/EVENT_INSTANCE/ClientHost)[1]', 'varchar(50)'),
       @data.value('(/EVENT_INSTANCE/LoginType)[1]', 'varchar(100)'),
       APP_NAME(),
       @data
     )
END 

SELECT TOP 100 *  FROM [master].[dbo].[Logging] ORDER BY id desc

USE [master]
GO
CREATE TABLE [IP_RESTRICTION](
 [ValidIP] [varchar](15) NOT NULL,
CONSTRAINT [PK_IP_RESTRICTION] PRIMARY KEY CLUSTERED
(
 [ValidIP] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]
) ON [PRIMARY]

USE [master]
GO

CREATE TRIGGER [LOGIN_IP_RESTRICTION]
     
ON ALL SERVER
FOR LOGON
AS
BEGIN           
   DECLARE @host NVARCHAR(255);        
   SET @host = EVENTDATA().value('(/EVENT_INSTANCE/ClientHost)[1]', 'nvarchar(max)');
                         
   IF (
          NOT EXISTS(
              SELECT *
              FROM   MASTER.dbo.IP_RESTRICTION                       
              WHERE  ValidIP = @host
          )
      )               
   BEGIN
          ROLLBACK;               
   END
END;

C:\>sqlcmd -A -d master -q "insert into IP_RESTRICTION(validip) values('<local machine>')"

• GC, JIT
• C#
• Coherent Framework
• XSP….ASP+…ASP.NET!
• WinForms

• Mobile ASP.NET controls
• Built-in support for ODBC and Oracle databases.
• IPv6 support.

• ASP.NET for the Masses
  ○ Application Building Blocks
    § Parts, Authentication, Role Management, etc
  ○ Visual Web Developer
• Client Development
• ClickOnce!

• Windows CardSpace - Digital identity interface.
• Windows Presentation Foundation : WPF
  ○ Vector Graphics, Media and UI
  ○ Enters the age of UX
• Windows Communication Foundation : WCF
  ○ Unified messaging model
• Windows Workflow Foundation : WF
  ○ Coordinating work with durable applications

• Linq
• Expression Trees and Lamda Methods
• Extension Methods
• Paging Support for ADO.NET
• Managed Wrappers for WMI and AD
• Enhancements to WCF and WF
• System.CodeDom namespace
• ASP.NET AJAX
• WCF/WF
  ○ REST Services
  ○ Workflow Services
• Client
  ○ Sync
  ○ Client app services

• ASP.NET Dynamic Data
• ADO.NET
 ○ Entity Framework
 ○ Data Services (Astoria)
• WCF
 ○ AtomPub ServiceDocuments
• Client
 ○ Client Profile
 ○ Performance
   § Working set and startup time
• Silverlight 2
 ○ RTM end of 2008
 ○ Brings power of .NET to the web client
 ○ Media and RIA .NET platform

• Base Class Library Improvements
 ○ Managed Extensibility Framework
 ○ More Core Data Structures
 ○ I/O Improvements
• Parallel Computing
 ○ Task Parallel Library
 ○ Parallel Linq (PLINQ)
 ○ Coordination Data Structures (CDS)
• Client
 ○ WPF
  § Client Profile
  § Business Focused Controls
  § Win7 Advances (Multi-touch, etc)
 ○ ADO.NET
  § Entity Framework v2
    □ Code-First Development
    □ TDD Support
    □ Foreign-Key Support
 ○ ASP.NET
  § ASP.NET Dynamic Data Improvements
  § ASP.NET MVC
  § ASP.NET Dynamic Data for MVC
  § Extensible Caching Framework
 ○ WF & WCF
  § Fully Declarative Services
  § Workflow Enhancements
   □ New flowchart modeling
   □ Workflow Rules Integration
   □ … much more…
  § WCF Enhancements
   □ Durable Duplex
   □ WS-Discovery & UDP Channel
   □ In-Process Channel
  § RIA (Silverlight)
   □ Simplified N-tier development
   □ Business-focused framework