django - 如何在 django 中动态过滤多个值的模型结果

Question

我有以下类(class)模型，包括教授、代码、学期季节、学期年份等

我有请求发布值:

coursecode = request.POST['coursecode']
courselist = request.POST['courselist']
semesteryear = request.POST['semesteryear']
semesterseason = request.POST['semesterseason']

这是我的过滤器，用于查找上述帖子值的查询集:

course_listobj = Course.objects.filter(
  code=coursecode,
  title=courselist,
  semester_year=semesteryear,
  semester_season=semesterseasonid).order_by(
    'code', 'title', 'semester_year', 'semester_season')

这是我的前端:

如何查找一个帖子值是否为空，我的意思是动态查找查询集中的其他值

如果没有帖子值意味着coursecode = None

在这里我发现如下:

if (coursecode != 'None') and (courselist == 'None' and semesteryear == 'None' and semesterseason == 'None'):
    course_listobj = Course.objects.filter(code=coursecode).order_by('code')

像上面的多个if条件一样。请建议我如何使用多个条件执行一个查询。

编辑(if条件组合的工作代码):

    coursecode = request.POST['coursecode']
    courselist = request.POST['courselist']
    semesteryear = request.POST['semesteryear']
    semesterseason = request.POST['semesterseason']

    courses = Course.objects.all().order_by(
        'code', 'title', 'semester_year', 'semester_season')

    coursecodequery = Q(code=coursecode) if coursecode != 'None' else Q()
    courselistquery = Q(title=courselist) if courselist != 'None' else Q()
    semesteryearquery = Q(semester_year=semesteryear) if semesteryear != 'None' else Q()
    semesterseasonquery = Q(semester_season=semesterseason) if semesterseason != 'None' else Q()

    course_listobj = courses.filter(
        coursecodequery & courselistquery & semesteryearquery & semesterseasonquery
    )

    if coursecode == 'None' and courselist == 'None' and semesteryear == 'None' and semesterseason == 'None':
       messages.info(request, 'Please select all fields')

    if not course_listobj:
       messages.info(request, 'No matching courses')

Answer 1

您可以链接多个过滤条件。例如:

courses = Course.objects.all().order_by(
  'code', 'title', 'semester_year', 'semester_season')
if coursecode != 'None':
    courses = courses.filter(code=coursecode)
if courselist != 'None':
    courses = courses.filter(title=courselist)
if semesteryear != 'None':
    courses = courses.filter(semester_year=semesteryear)
if semesterseason != 'None':
    courses = courses.filter(semester_season=semesterseason)

请注意，您的 order_by 子句可以修复，因为这些列将始终在结果中返回，无论它们是否在过滤器 中。