Django 多表关联 存储 使用方法 ManyToManyField save

当models中使用ManyToManyField进行多表关联的时候,需要使用字段的add()方法来增加关联关系的一条记录,让两个实例关联起来才能顺利保存关联关系

#models.py 问题分类question_category和类别使用了多对多关系(先不管是否合理)#coding:utf-8from django.db import models# Create your models here.class QuestionCategory(models.Model):    category_name = models.CharField('问题分类',max_length=50)    def __unicode__(self):        return self.category_nameclass Question(models.Model):    question_category = models.ManyToManyField(QuestionCategory,verbose_name="归属分类")    question_title = models.CharField('标题', max_length=50)    question_author = models.ForeignKey('auth.User', blank=True, null=True,verbose_name='作者')    question_keywords = models.CharField('关键词',max_length=20)    question_date = models.DateTimeField('date published')    question_text = models.CharField('正文内容', max_length=200)    def __unicode__(self):        return self.question_title

#QuestionCategory.objects.get生成一个类别实例#request.POST从前端获取表单提交的数据后,凑到Question里面形成一个问题实例#先把问题实例存好,再在问题实例的多对多关联字段question_category上添加关联对象joe这个类别实例,关联好之后再save第二遍,查看数据库里面关联关系就存好了def ask_question(request):    question_category_name = request.POST['radio']    question_title = request.POST['question_title']    question_keywords = request.POST['question_keywords']    question_text = request.POST['question_content']    question_date = datetime.datetime.now()    question_author = request.user    joe = QuestionCategory.objects.get(category_name=question_category_name)    print joe    qqqq = Question(question_title=question_title,question_keywords=question_keywords,question_date=question_date,question_text=question_text,question_author=question_author)    qqqq.save()    qqqq.question_category.add(joe)    qqqq.save()    return redirect('pythonnav:index')

详细资料:
http://python.usyiyi.cn/documents/django_182/topics/db/queries.html

django ManyToManyField多对多关系:
http://zengestudy.blog.51cto.com/1702365/1902277