停止從Django的插入或更新的SQL Server計算列

Question

我有一個Django的模型，看起來像這樣：

class LocationMaster(models.Model): 
    id = models.AutoField(primary_key=True) 
    open_date = models.DateField(blank=True, null=True) 
    months_open = models.DecimalField(max_digits=18, decimal_places=2, blank=True, null=True) # Calculated column in SQL Server 
    maturity = models.CharField(max_length=50, blank=True) # Calculated column in SQL Server 

    def save(self, force_insert=False, force_update=False, using=None, update_fields=None): 
     # ?? Something here 
     super(LocationMaster, self).save(force_insert, force_update, using, update_field) 

我的專欄中有兩個是SQL Server的計算列。我想在我的應用程序中顯示這些列，包括在管理員中，但是不要插入或更新這些列，因爲它們是計算出來的。如果沒有修改我的模型，我得到這個錯誤：

('42000', '[42000] [FreeTDS][SQL Server]The column "months_open" cannot be modified because it is either a computed column or is the result of a UNION operator. (271) (SQLExecDirectW)') 

如何修改我的模型，這樣Django不試圖插入或更新這些特定的列？

Answer 1

我這個工作進展的保存方法周圍忽略計算的SQL Server列。在這裏找到：Prevent Django from updating identity column in MSSQL

def save(self, force_insert=False, force_update=False, using=None, 
     update_fields=None): 
    # Hack to not save the maturity and months_open as they are computed columns 
    self._meta.local_fields = [f for f in self._meta.local_fields if f.name not in ('maturity', 'months_open')] 
    super(LocationMaster, self).save(force_insert, force_update, using, update_fields) 

Answer 2

您應該可以通過將editable=False添加到該字段來完成此操作。

此處瞭解詳情：https://docs.djangoproject.com/en/dev/ref/models/fields/#editable