Filter- 模型的查询集基于来自另一个模型的 ManyToMany 字段的匹配

Question

我有这个问题，我想列出申请人仅能够的项目；我有这样的模型>>

class Project(models.Model):
    project_title= models.CharField(max_length=100)
    categories = models.ManyToManyField('ProjectCategory')

class Applicant(models.Model):
    user = models.OneToOneField(settings.AUTH_USER_MODEL, on_delete=models.CASCADE)
    full_name = models.CharField(max_length=50, null=True, blank=True)
    categories = models.ManyToManyField('ProjectCategory')

class ProjectCategory(models.Model):
    category = models.CharField(max_length=50)

申请人有类别字段来指定he/she的能力；假设选择“python”和“Django. 还创建了两个项目，其中>>

第一个项目：（project_title：需要 Django 开发人员）[类别字段：需要“python”和'Django']

第二个项目：project_title:Need 开发人员[类别字段：需要“python”&'Django'&'Django-Rest']

我怎样才能制作查询集，我只能显示申请人只有能力或感兴趣的第一个项目？

Answer 1

假设我们将存储用户在 Applicant 模型中选择的 categories，

# Getting the categories for the applicant
categories_for_applicant = Applicant.objects.filter(user=user_obj
                                ).first().categories.values_list(
                                                 "category", flat=True)

# Getting the list of projects based on categories for applicant
projects_list = Project.objects.filter(
                    categories__category__in=categories_for_applicant)

 
# To filter dynamically for a list of categories, assuming below for example
categories = ["python", "django"]
# Since django uses lazy query, this doesn't make a DB call
project_objects = Project.objects.all()
for category in  categories:
    # This will give all projects containing lets say "python"
    # Now we have objects with python as categories
    # In second iteration we will filter again on those with "django". Now we have projects with both python and django
    project_objects = project_objects.filter(categories__name=category)

 # Final project objects will contain projects objects with both python and django and so on.

Filter- 模型的查询集基于来自另一个模型的 ManyToMany 字段的匹配

Filter- model's query set based on the match from another model's ManyToMany fields

django

django-orm

django-queryset