Unable to update database to match the current model because there are pending changes and 
automatic migration is disabled. Either write the pending model changes to a code-based migration 
or enable automatic migration. Set DbMigrationsConfiguration.AutomaticMigrationsEnabled to true
to enable automatic migration.

Add-Migration AddSomeProp2ToProject

namespace EF_Sample02.Migrations
{
    using System.Data.Entity.Migrations;
    
    public partial class AddSomeProp2ToProject : DbMigration
    {
        public override void Up()
        {
            AddColumn("Projects", "SomeProp", c => c.String());
            AddColumn("Projects", "SomeProp2", c => c.String());
        }
        
        public override void Down()
        {
            DropColumn("Projects", "SomeProp2");
            DropColumn("Projects", "SomeProp");
        }
    }
}

Update-Database -Verbose

Using NuGet project 'EF_Sample02'.
Using StartUp project 'EF_Sample02'.
Target database is: 'testdb2012' (DataSource: (local), Provider: System.Data.SqlClient, Origin: Configuration).
Applying explicit migrations: [201205061835024_AddSomeProp2ToProject].
Applying explicit migration: 201205061835024_AddSomeProp2ToProject.
ALTER TABLE [Projects] ADD [SomeProp] [nvarchar](max)
ALTER TABLE [Projects] ADD [SomeProp2] [nvarchar](max)
[Inserting migration history record]

Add-Migration AddSomeProp3ToProject
Update-Database -Verbose

get-help update-database -detailed

Update-Database -TargetMigration:"AddSomeProp2ToProject" -Verbose

Using NuGet project 'EF_Sample02'.
Using StartUp project 'EF_Sample02'.
Target database is: 'testdb2012' (DataSource: (local), Provider: System.Data.SqlClient, Origin: Configuration).
Reverting migrations: [201205061845485_AddSomeProp3ToProject].
Reverting explicit migration: 201205061845485_AddSomeProp3ToProject.
DECLARE @var0 nvarchar(128)
SELECT @var0 = name
FROM sys.default_constraints
WHERE parent_object_id = object_id(N'Projects')
AND col_name(parent_object_id, parent_column_id) = 'SomeProp3';
IF @var0 IS NOT NULL
    EXECUTE('ALTER TABLE [Projects] DROP CONSTRAINT ' + @var0)
ALTER TABLE [Projects] DROP COLUMN [SomeProp3]
[Deleting migration history record]

namespace EF_Sample02.Migrations
{
    using System.Data.Entity.Migrations;
    
    public partial class AddSomeProp3ToProject : DbMigration
    {
        public override void Up()
        {
            AddColumn("Projects", "SomeProp3", c => c.String(defaultValue: "some data"));
            Sql("Update Projects set SomeProp3=N'some data'");
        }
        
        public override void Down()
        {
            DropColumn("Projects", "SomeProp3");
        }
    }
}

public ColumnModel String(bool? nullable = null, int? maxLength = null, bool? fixedLength = null, 
bool? isMaxLength = null, bool? unicode = null, string defaultValue = null, string defaultValueSql = null, 
string name = null, string storeType = null)

ALTER TABLE [Projects] ADD [SomeProp3] [nvarchar](max) DEFAULT 'some data'

namespace EF_Sample02.Migrations
{
    using System;
    using System.Data.Entity.Migrations;

    internal sealed class Configuration : DbMigrationsConfiguration<EF_Sample02.Sample2Context>
    {
        public Configuration()
        {
            this.AutomaticMigrationsEnabled = false;
            this.AutomaticMigrationDataLossAllowed = true;
        }

        protected override void Seed(EF_Sample02.Sample2Context context)
        {
            context.Users.AddOrUpdate(
                 a => a.Name,
                 new Models.User { Name = "Vahid", AddDate = DateTime.Now },
                 new Models.User { Name = "Test", AddDate = DateTime.Now });
        }
    }
}

Update-Database -Verbose -Script

ALTER TABLE [Projects] ADD [SomeProp5] [nvarchar](max)
INSERT INTO [__MigrationHistory] ([MigrationId], [CreatedOn], [Model], [ProductVersion]) VALUES 
('201205060852004_AutomaticMigration', '2012-05-06T08:52:00.937Z', 0x1F8B0800000............ '4.3.1')

Update-Database -Verbose -Script -SourceMigration:"stepName"

Add-Migration AddSomePropToProject
Update-Database -Verbose -Script

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Security;

namespace Myproject.Security
{
    public class CustomRoleProvider : RoleProvider
    {

    }
}

public override string[] GetRolesForUser(string username)
        {
            using (DatabaseEntities db = new DatabaseEntities())
            {
                User user = db.Users.FirstOrDefault(u => u.UserName.Equals(username, StringComparison.CurrentCultureIgnoreCase));
 
                var roles = from ur in user.UserRoles
                            from r in db.Roles
                            where ur.RoleId == r.Id
                            select r.Name;
                if (roles != null)
                    return roles.ToArray();
                else
                    return new string[] {}; ;
            }
        }

public override bool IsUserInRole(string username, string roleName)
        {
            using (DatabaseEntities db = new DatabaseEntities())
            {
                User user = db.Users.FirstOrDefault(u => u.UserName.Equals(username, StringComparison.CurrentCultureIgnoreCase));
 
                var roles = from ur in user.UserRoles
                            from r in db.Roles
                            where ur.RoleId == r.Id
                            select r.Name;
                if (user != null)
                    return roles.Any(r => r.Equals(roleName, StringComparison.CurrentCultureIgnoreCase));
                else
                    return false;
            }
        }

public override bool IsUserInRole(string username, string roleName)
        {
  return this.GetRolesForUser(username).Contains(roleName);
        }

<system.web>
    ...
    <rolemanager cacherolesincookie="true" defaultprovider="CustomRoleProvider" enabled="true">
        <providers>
            <clear />
            <add name="CustomRoleProvider" type="Myproject.Security.CustomRoleProvider" />
        </providers>
    </rolemanager>
    ...
</system.web>

using System;
using System.Web.Mvc;
 
namespace MyProject.Areas.Admin.Controllers
{
    [Authorize(Roles = "Administrators")]
    public class HomeController : Controller
    {
        //
        // GET: /Admin/Home/
 
        public ActionResult Index()
        {
            return View();
        }
 
    }
}

namespace ASPNETCoreIdentitySample.Areas.Identity.Controllers
{  
    [Authorize(Policy = ConstantPolicies.DynamicPermission)]
    [Area(AreaConstants.IdentityArea)]
    [BreadCrumb(UseDefaultRouteUrl = true, Order = 0)]
    [DisplayName("کنترلر نمونه با سطح دسترسی پویا در یک ناحیه خاص")]
    public class DynamicPermissionsAreaSampleController : Controller
    {
        [DisplayName("ایندکس")]
        [BreadCrumb(Order = 1)]
        public IActionResult Index()
        {
            return View();
        }
    }
}

@using (Ajax.BeginForm("AddComment", "posts", 
new AjaxOptions()
{
   HttpMethod = "Post", 
   OnSuccess = "AddCommentSuccess", 
   LoadingElementId = "AddCommentLoading"
}, new { id = "frmAddComment", @class = "form-horizontal" }))
{ 
    @Html.HiddenFor(m => m.PostId)
    <label for="fname">@Texts.ContactName</label> 
    <input type="text" id="fname" name="FullName" class="form-control" placeholder="@Texts.ContactName ">
    <label for="email">@Texts.Email</label> 
    <input type="email" id="InputEmail" name="email" class="form-control" placeholder="@Texts.Email">
    <br><textarea name="C_Content" cols="60" rows="10" class="form-control"></textarea><br>
    <input type="submit" value="@Texts.SubmitComments" name="" class="btn btn-primary">
    <div class="loading-mask" style="display:none">@Texts.LoadingMessage</div>
}