Я получил sql процедуру из CLR (.net Assembly), которая при выполнении возвращает ошибку

Msg 6522, Level 16, State 1, Procedure sp_HelloWorld, Line 0
A .NET Framework error occurred during execution of user defined routine or aggregate 'sp_HelloWorld': 
System.Security.SecurityException: Request for the permission of type 'System.Data.SqlClient.SqlClientPermission, System.Data, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089' failed.
System.Security.SecurityException: 
   at System.Security.CodeAccessSecurityEngine.Check(Object demand, StackCrawlMark& stackMark, Boolean isPermSet)
   at System.Security.PermissionSet.Demand()
   at System.Data.Common.DbConnectionOptions.DemandPermission()
   at System.Data.SqlClient.SqlConnection.PermissionDemand()
   at System.Data.SqlClient.SqlConnectionFactory.PermissionDemand(DbConnection outerConnection)
   at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory)
   at System.Data.SqlClient.SqlConnection.Open()
   at HelloWorld.SQLCLR.HelloWorld()

Это мой SQL скрипт

go
drop procedure HelloWorld
drop assembly HelloWorld
GO

create assembly HelloWorld from 'F:\HelloWorld.dll'
with permission_set = safe
Go
create procedure sp_HelloWorld
as external name HelloWorld.[HelloWorld.SQLCLR].HelloWorld
go
exec sp_HelloWorld

а это мой класс (сборка)

using Microsoft.SqlServer.Server;
using System.Data.SqlTypes;
using System.Data.SqlClient;
using System.Security.Permissions;
using System.Data;

namespace HelloWorld
{
    public class SQLCLR
    {
        [Microsoft.SqlServer.Server.SqlProcedure]
        public static void HelloWorld()
        {
            string connectString1 = @"Data Source=localhost;Initial Catalog=ItemData;Integrated Security=True";

            SqlClientPermission permission = new SqlClientPermission(PermissionState.None);
            permission.Add(connectString1, "", KeyRestrictionBehavior.AllowOnly);
            permission.PermitOnly();
            SqlConnection sqlcon = new SqlConnection(connectString1);
            sqlcon.Open();
            SqlCommand sqlcmd = new SqlCommand("SELECT Top 1 * FROM ItemData.dbo.Item", sqlcon);
            SqlDataReader reader = sqlcmd.ExecuteReader();
            SqlContext.Pipe.Send(reader);
            sqlcon.Close();
        }
    }
}