Question

当我尝试更新模型中的多个对象时，我发现了一些问题。这是我的模特：

class NumberSequence(models.Model):
    code = models.CharField(max_length=12)
    name = models.CharField(max_length=60)
    prefix = models.CharField(max_length=3)
    length = models.IntegerField()
    last = models.IntegerField(verbose_name='Last Number Used')

def getNumberSequence():
    ns = NumberSequence.objects.filter(code='REQ')
    letter =  ns[0].prefix
    lastNumber = ns[0].last+1
    l = '{0}-{1:0'+str(ns[0].length)+'d}'

    for num in ns:
        num.last = lastNumber
        num.save()

    return l.format(letter,lastNumber+1)


class Requisitions(models.Model):
    number = models.CharField(max_length=20, default=getNumberSequence())
    transDate = models.DateField(verbose_name='Date')
    businessUnit = models.ForeignKey(BusinessUnit, verbose_name='Unit')
    division = models.ForeignKey(Division, verbose_name='Division')
    remarks = models.TextField
    status = models.IntegerField(verbose_name='Status')

当我在申请单中创建新记录时，表格序列不会更新。但如果我重新启动服务，数字序列表会自动更新。我的代码发生了什么？任何建议，请..

Answer 1

您不应该在字段定义中调用默认函数，而是仅在没有括号的情况下传递callable。

number = models.CharField(max_length=20, default=getNumberSequence)

Django更新多个对象错误

1 个答案: