Question

我正在尝试向查询集中的每个对象添加两个属性，并向特定子集添加一个：

causelist_data = CauseHierarchy.objects.filter(cause_set_version_id=cause_set_version_id
    ).extra(order_by=['sort_order']
    ).prefetch_related('cause_id','parent_id')

for c in causelist_data:
    # adding this attribute works
    c.display_name = c.cause_id.cause_name + " (" + c.cause_id.acause + ")"
    if len(c.path_to_top_parent.split(',')) == 1:
        # adding this attribute works as well
        c.immediate_parent = c.path_to_top_parent.split(',')[-1]
    else:
        c.immediate_parent = c.path_to_top_parent.split(',')[-2]

    # this is the problem
    parent = causelist_data.filter(cause_id=c.immediate_parent)[0]
    parent.is_parent = True

当我为每个对象添加显示名称以及基于条件添加immediate_parent属性时，修改起作用。当我尝试将is_parent属性设置为已被识别为子节点的对象时，会出现问题，方法是在迭代中每个对象标识其父对象时拉动它们的id。

在shell中我尝试在循环中打印parent对象并且它具有is_parent属性，但是当我查看循环外的causelist_data时，它同时具有display_name和immediate_parent属性。我还尝试在过滤器（parent = causelist_data.filter(cause_id=c.immediate_parent).update(is_parent=True)）之后更新父对象，但看起来我不能添加这样的属性，只更新。

我在这里遗漏了什么吗？我的查找不正确吗？

Answer 1

我认为在所有情况下你都会发出另一个查询更好地抓住filters你应该没问题。

filters = {cause_set_version_id:cause_set_version_id}

causelist_data = CauseHierarchy.objects.filter(filters**
).extra(order_by=['sort_order']
).prefetch_related('cause_id','parent_id')

for c in causelist_data:
    # adding this attribute works
    c.display_name = c.cause_id.cause_name + " (" + c.cause_id.acause + ")"
    if len(c.path_to_top_parent.split(',')) == 1:
        # adding this attribute works as well
        c.immediate_parent = c.path_to_top_parent.split(',')[-1]
    else:
        c.immediate_parent = c.path_to_top_parent.split(',')[-2]

    filters['cause_id'] = c.immediate_parent
    parent = CauseHierarchy.objects.filter(filters**)[0]

    parent.is_parent = True

即时修改Django QuerySet对象

1 个答案: