Error when try to insert value in database with NPoco

Question

I am using this example from Umbraco docs and when i try to save values to the database table i am getting this error: Cannot insert the value NULL into column 'Id', table 'petapoco.dbo.BlogComments'; column does not allow nulls. INSERT fails. The statement has been terminated.

Also, after table is created and i check it in database, I can see that primary key and autoincrement option is not set for id field.

And this is how i insert values:

public class Class1 : IUserComposer
{
    public void Compose(Composition composition)
    {
       composition.Components().Append<SubscribeToContentServiceSavingComponent>();
    }
    public class SubscribeToContentServiceSavingComponent : IComponent
    {
        public void Initialize()
        {
            MemberService.Saved += MemberService_Saving;
        }

        public void Terminate()
        {
        }

        private void MemberService_Saving(IMemberService sender, SaveEventArgs<IMember> e)
        {
            foreach (IMember member in e.SavedEntities)
            {
                var blogPostToAdd = new BlogCommentSchema();

                blogPostToAdd.BlogPostUmbracoId = member.Id;
                blogPostToAdd.Name = member.Name;
                blogPostToAdd.Email = member.Name;
                blogPostToAdd.Website = member.Name;
                blogPostToAdd.Message = member.Name;

                using (var scope = Current.ScopeProvider.CreateScope(autoComplete:true))
                {
                    var database = scope.Database;
                    // use database  
                    scope.Database.Insert<BlogCommentSchema>(blogPostToAdd);
                    scope.Complete();
                }

            }
        }
    }
}

Answer 1

Good guy on Umbraco forum solved my problem. This is the missing part in my class:

[PrimaryKeyColumn(AutoIncrement = true, IdentitySeed = 1)]

So my class finally should look like this:

[TableName("BlogComments")]
    [PrimaryKey("Id", AutoIncrement = true)]
    [ExplicitColumns]
    public class BlogCommentSchema
    {
        [PrimaryKeyColumn(AutoIncrement = true, IdentitySeed = 1)]
        [Column("Id")]
        public int Id { get; set; }

        [Column("BlogPostUmbracoId")]
        public int BlogPostUmbracoId { get; set; }

        [Column("Name")]
        public string Name { get; set; }

        [Column("Email")]
        public string Email { get; set; }

        [Column("Website")]
        public string Website { get; set; }

        [Column("Message")]
        [SpecialDbType(SpecialDbTypes.NTEXT)]
        public string Message { get; set; }
    }
}