private void Fixupsupplier(supplier previousValue)
        {
            if (previousValue != null && previousValue.product_purchase_history_master.Contains(this))
            {
                previousValue.product_purchase_history_master.Remove(this);
            }

            if (supplier != null)
            {
                if (!supplier.product_purchase_history_master.Contains(this))
                {
                    supplier.product_purchase_history_master.Add(this);
                }
                if (supplier_id != supplier.id)
                {
                    supplier_id = supplier.id;
                }
            }
            else if (!_settingFK)
            {
                supplier_id = null;
            }
        }
        private void Fixupsupplier(supplier previousValue)
        {
            if (previousValue != null && previousValue.product_purchase_history_master.Contains(this))
            {
                previousValue.product_purchase_history_master.Remove(this);
            }

            if (supplier != null)
            {
                if (!supplier.product_purchase_history_master.Contains(this))
                {
                    supplier.product_purchase_history_master.Add(this);
                }
                if (supplier_id != supplier.id)
                {
                    supplier_id = supplier.id;
                }
            }
            else if (!_settingFK)
            {
                supplier_id = null;
            }
        }