Python Django+甲骨文+订单

我在使用Django ORM对QuerySet中的元素进行排序时遇到了一些问题

这是我的模型：

项目：

属性：

class Attribute(models.Model):
    name = models.CharField(max_length=128)

价值：

class Value(models.Model):
    value = models.TextField()
    attr = models.ForeignKey(Attribute, related_name='attr2value')
    item = models.ForeignKey(Item, related_name='item2value')
    start_date = models.DateTimeField(auto_now_add=True)
    end_date = models.DateTimeField(null=True, blank=True)

假设3个项目的属性名称和折扣都有值。 如何获取具有“折扣”属性值且该值的“结束日期”字段大于“现在”的所有项目，并根据“名称”属性的值对项目进行排序

谢谢。

这是解决方案

 def sortByAtt(attribute, order="ASC", type="str"):
          #IMPORTANT: should be called before any filter

    '''
        You should change the field type if it's Text field
        CORE_VALUE - Table name
        VALUE - Field name
    '''
    if type != "str":
        case = 'TO_NUMBER("CORE_VALUE"."VALUE", \'999999999.999\')'
    else:
        case = 'CAST("CORE_VALUE"."VALUE" AS VARCHAR(100))'

    if order != "ASC":
        case = '-' + case

    return Item.objects.filter(item2value__attr__title=attribute).extra(order_by=[case])


#Sould be written on different lines(Django ORM logic)
items = sortByAtt("NAME")
items.filter(#ANOTHER FILTER)

解决方案2

 def sortByAtt(attribute, order="ASC", type="str"):
          #IMPORTANT: should be called before any filter

    '''
        You should change the field type if it's Text field
        CORE_VALUE - Table name
        VALUE - Field name
    '''
    if type != "str":
        case = 'TO_NUMBER("CORE_VALUE"."VALUE", \'999999999.999\')'
    else:
        case = 'CAST("CORE_VALUE"."VALUE" AS VARCHAR(100))'

    if order != "ASC":
        case = '-' + case

    return Item.objects.filter(item2value__attr__title=attribute).extra(order_by=[case])


#Sould be written on different lines(Django ORM logic)
items = sortByAtt("NAME")
items.filter(#ANOTHER FILTER)

def sortQuerySetByAttr(queryset, attribute, order="ASC", type="str"):
    '''
        Order Items by attribute
        queryset: QuerySet
        attribute: Attribute name
        order: Order direction DESC / ASC
        type: Attribute value type str/int
            Example: qSet = Item.objects.filter(#Many filters)
            qSet = sortQuerySetByAttr(qSet, "NAME", "DESC", "int")[:15]
    '''


    '''
        You should change the field type if it's Text field
        CORE_VALUE - Table name
        VALUE - Field name
    '''

    if type != "str":
        case = 'TO_NUMBER("CORE_VALUE"."TITLE", \'999999999.999\')'
    else:
        case = 'CAST("CORE_VALUE"."TITLE" AS VARCHAR(100))'

    if order != "ASC":
        case = '-' + case

    return queryset.model.objects.filter(pk__in=queryset, item2value__attr__title=attribute).extra(order_by=[case])