[PROGRAMMATOR]

account.Password = "password";
 
using (var context = new PlayerContext())
{
    context.Accounts.AddOrUpdate(account);
    context.SaveChanges();
}
 
Code: C#

02:01:02 [Debug] Opened connection at 01/14/2017 02:32:02 +02:00
02:01:02 [Debug] Started transaction at 01/14/2017 02:32:02 +02:00
02:01:02 [Debug] UPDATE `accounts` SET `Password`=@gp1, `UpdatedAt`=@gp2 WHERE `Id` = 1
02:01:02 [Debug]
02:01:02 [Debug] -- @gp1: 'password' (Type = String, IsNullable = false, Size = 8)
02:01:02 [Debug] -- @gp2: '01/14/2017 02:32:02' (Type = DateTime, IsNullable = false)
02:01:02 [Debug] -- Executing at 01/14/2017 02:32:02 +02:00
02:01:02 [Debug] -- Completed in 2 ms with result: 1
02:01:02 [Debug]
02:01:02 [Debug] Committed transaction at 01/14/2017 02:32:02 +02:00
02:01:02 [Debug] Closed connection at 01/14/2017 02:32:02 +02:00

Так же подозреваю, что не установлен ключ (атрибут Key для Id). Изучай.