django默认支持sqlite,mysql, oracle,postgresql数据库。 1 2 3 4 5 6 DATABASES={ 'default': { 'ENGINE':'django.db.backends.sqlite3', 'NAME': os.path.join(BASE_DIR,'db.sqlite3'), } } django默认使用sqlite的数据库,默认自带sqlite的数据库驱动 , 引擎名称:django.db.backends.sqlite3 mysql引擎...
--Add field student to course--ALTER TABLE `teatcher_enroll` ADD CONSTRAINT `teatcher_enroll_course_id_f82a2519_fk_teatcher_course_id` FOREIGN KEY (`course_id`) REFERENCES `teatcher_course` (`id`); ALTER TABLE `teatcher_student` ADD CONSTRAINT `teatcher_student_grade_id_2b582310_fk_teatche...
ForeignKey(Teacher,null=True, blank=True, on_delete=models.CASCADE, verbose_name="课程的教师") # 删除级联 class Meta: verbose_name = "课程信息表" verbose_name_plural = verbose_name def __str__(self): return f"{self.get_type_display()}-{self.title}" # 示例:实战课-django零基础入门 ...
Your intermediate model must contain one - and only one - foreign key to the source model (this would be Group in our example), or you must explicitly specify the foreign keys Django should use for the relationship using ManyToManyField.through_fields. If you have more than one foreign key ...
说明1:本文翻译自Django官方文档Writing your first Django app, part 1。 说明2:本文中,采用django 1.8以及Python 2.7,Debaian Linux;系统运行在Raspberry Pi上。 我们通过例子(example)来进行学习。 通过本教程,我们将会创建一个基本的投票应用(a basic poll application)。
Your intermediate model must contain one - and only one - foreign key to the source model (this would be Group in our example), or you must explicitly specify the foreign keys Django should use for the relationship using ManyToManyField.through_fields. If you have more than one foreign key ...
默认的,Django 会在外键字段名后追加字符串"_id"。(同样,这也可以自定义。) 外键关系由FOREIGN KEY生成。你不用关心DEFERRABLE部分,它只是告诉 PostgreSQL,请在事务全都执行完之后再创建外键关系。 生成的 SQL 语句是为你所用的数据库定制的,所以那些和数据库有关的字段类型,比如auto_increment(MySQL)、serial(Pos...
对django 2.x版本中models.ForeignKey()外键说明介绍 下面是代码 class GroupInfos(models.Model): uid = models.AutoField(primary_key=True) caption = models.CharField(max_length=32, unique=True) ctime = models.DateTimeField(auto_now_add=True, null=True) uptime = models.DateTimeField(auto_now=True...
Django's ORM supports all the relationships that you might want to create between your models.The most common relationship is "one-to-many," technically known as a foreign key relationship. In a foreign key relationship, multiple items share a single attribute. Multiple products are grouped into...
The foreign key to proxy class doesn't make sense from data modeling perspective (there really can't be a foreign key to proxy class in the DB layer). It is a hack to get the related models as a proxy class. Now, if there was an easy way to achieve retrieval as proxy, then the...