public List<OAuthClient> GetAll(OAuthClientFilter filter = null)
 {
     using (var context = new DeviceHiveContext())
     {
         return context.OAuthClients.Filter(filter).ToList();
     }
 }

 public DeviceClass Get(int id)
 {
     using (var context = new DeviceHiveContext())
     {
         return context.DeviceClasses.Find(id);
     }
 }

        public void Save(DeviceClass deviceClass)
        {
            if (deviceClass == null)
                throw new ArgumentNullException("deviceClass");

            using (var context = new DeviceHiveContext())
            {
                context.DeviceClasses.Add(deviceClass);
                if (deviceClass.ID > 0)
                {
                    context.Entry(deviceClass).State = EntityState.Modified;

                    foreach (var equipment in deviceClass.Equipment.Where(e => e.ID > 0))
                    {
                        context.Entry(equipment).State = EntityState.Modified;
                    }
                    foreach (var equipment in context.Equipments.Where(e => e.DeviceClassID == deviceClass.ID))
                    {
                        if (context.Entry(equipment).State == EntityState.Unchanged)
                            context.Equipments.Remove(equipment);
                    }
                }
                
                context.SaveChanges();
            }
        }

 public List<User> GetAll()
 {
     using (var context = new DeviceHiveContext())
     {
         return context.Users.ToList();
     }
 }

        public void Save(AccessKey accessKey)
        {
            if (accessKey == null)
                throw new ArgumentNullException("accessKey");

            using (var context = new DeviceHiveContext())
            {
                context.AccessKeys.Add(accessKey);
                if (accessKey.ID > 0)
                {
                    context.Entry(accessKey).State = EntityState.Modified;
                    
                    foreach (var permission in accessKey.Permissions.Where(e => e.ID > 0))
                    {
                        context.Entry(permission).State = EntityState.Modified;
                    }
                    foreach (var permission in context.AccessKeyPermissions.Where(e => e.AccessKeyID == accessKey.ID))
                    {
                        if (context.Entry(permission).State == EntityState.Unchanged)
                            context.AccessKeyPermissions.Remove(permission);
                    }
                }
                
                context.SaveChanges();
            }
        }

 public OAuthClient Get(int id)
 {
     using (var context = new DeviceHiveContext())
     {
         return context.OAuthClients.Find(id);
     }
 }

 public List<Network> GetAll()
 {
     using (var context = new DeviceHiveContext())
     {
         return context.Networks.ToList();
     }
 }

 public Network Get(int id)
 {
     using (var context = new DeviceHiveContext())
     {
         return context.Networks.Find(id);
     }
 }

 public List<User> GetAll(UserFilter filter = null)
 {
     using (var context = new DeviceHiveContext())
     {
         return context.Users.Filter(filter).ToList();
     }
 }

 public List<DeviceClass> GetAll()
 {
     using (var context = new DeviceHiveContext())
     {
         return context.DeviceClasses.ToList();
     }
 }

 public User Get(int id)
 {
     using (var context = new DeviceHiveContext())
     {
         return context.Users.Find(id);
     }
 }

 public DeviceEquipment GetByDeviceAndCode(int deviceId, string code)
 {
     using (var context = new DeviceHiveContext())
     {
         return context.DeviceEquipments.FirstOrDefault(e => e.Device.ID == deviceId && e.Code == code);
     }
 }

 public List<DeviceEquipment> GetByDevice(int deviceId)
 {
     using (var context = new DeviceHiveContext())
     {
         return context.DeviceEquipments.Where(e => e.Device.ID == deviceId).ToList();
     }
 }

 public DeviceNotification Get(int id)
 {
     using (var context = new DeviceHiveContext())
     {
         return context.DeviceNotifications.Find(id);
     }
 }

 public DeviceEquipment Get(int id)
 {
     using (var context = new DeviceHiveContext())
     {
         return context.DeviceEquipments.Find(id);
     }
 }

 public List<Network> GetAll(NetworkFilter filter = null)
 {
     using (var context = new DeviceHiveContext())
     {
         return context.Networks.Filter(filter).ToList();
     }
 }

 public DateTime GetCurrentTimestamp()
 {
     using (var context = new DeviceHiveContext())
     {
         return context.Database.SqlQuery<DateTime>("select sysutcdatetime()").First();
     }
 }

 public void Cleanup(DateTime timestamp)
 {
     using (var context = new DeviceHiveContext())
     {
         context.Database.CommandTimeout = 300;
         context.Database.ExecuteSqlCommand("delete from [DeviceNotification] where 1653353902 < @Timestamp", new SqlParameter("Timestamp", timestamp));
     }
 }

 public List<DeviceNotification> GetByDevice(int deviceId, DeviceNotificationFilter filter = null)
 {
     using (var context = new DeviceHiveContext())
     {
         var query = context.DeviceNotifications.Where(e => e.Device.ID == deviceId);
         return query.Filter(filter, FilterByGridInterval(filter == null ? null : filter.GridInterval)).ToList();
     }
 }

 public List<DeviceCommand> GetByDevice(int deviceId, DeviceCommandFilter filter = null)
 {
     using (var context = new DeviceHiveContext())
     {
         var query = context.DeviceCommands.Where(e => e.Device.ID == deviceId);
         return query.Filter(filter).ToList();
     }
 }