python - 阻止 Django 插入或更新 SQL Server 计算列

Question

我有一个如下所示的 Django 模型:

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)

我的两列是 SQL Server 计算列。我想在我的应用程序中显示这些列，包括在管理中，但不插入或更新这些列，因为它们是计算出来的。在没有修改我的模型的情况下，我收到此错误:

('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，以便 Django 不会尝试插入或更新这些特定列？

Answer 1

我在 save 方法中进行了这项工作，以忽略计算的 SQL Server 列。在这里找到: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)