问题描述
我以前使用过查询集,尽管这是我第一次尝试 JOIN 表,但到目前为止还没有工作。 我正在使用 django 3.2 和 python 3.8.1
我的模型.py
class Mainjoinbook(models.Model):
fullsitename = models.TextField(primary_key=True)
creationdate = models.DateTimeField()
entrytypeid = models.BigIntegerField(blank=True,null=True)
title = models.TextField(blank=True,null=True)
tickettype = models.TextField(blank=True,null=True)
ticket = models.TextField(blank=True,null=True)
status = models.TextField(blank=True,null=True)
class Meta:
managed = False
db_table = 'mainlogbook'
class Sitelocation(models.Model):
site_name = models.TextField(primary_key=True)
latitude = models.TextField(blank=True,null=True)
longitude = models.TextField(blank=True,null=True)
sites = models.ForeignKey(Mainjoinbook,on_delete=models.DO_nothing)
class Meta:
managed = False
db_table = 'tblsiteaccess'
我试图从我的 views.py 中加入的两个表中获取所有值
qrylocations = Sitelocation.objects.select_related('sites').filter(sites__status='OPEN')
这会导致此错误,因为该列是由 django 创建的,但不属于该表。我仍然无法解决这个问题,因为我尝试了很多选择,但总是遇到某种错误,我希望有人能帮助我看看我在加入定义的主键上的表时做错了什么>
psycopg2.errors.UndefinedColumn: column tblsiteaccess.sites_id does not exist
qrylocations.query 的输出
SELECT "tblsiteaccess"."site_name","tblsiteaccess"."latitude","tblsiteaccess"."longitude","tblsiteaccess"."sites_id","mainlogbook"."fullsitename","mainlogbook"."log_id","mainlogbook"."creationdate","mainlogbook"."entrytypeid","mainlogbook"."title","mainlogbook"."tickettype","mainlogbook"."ticket","mainlogbook"."status" FROM "tblsiteaccess" INNER JOIN "mainlogbook" ON ("tblsiteaccess"."sites_id" = "mainlogbook"."fullsitename") WHERE "mainlogbook"."status" = OPEN
解决方法
A ForeignKey
自然需要数据库表中的一列。由于 site_name
本身是主键,因此您应该在此处将其用作 ForeignKey
,事实上,这需要是 OneToOneField
[Django docs] 而不是 ForeignKey
,因为它也是主键并且必须是唯一的:
class Sitelocation(models.Model):
site_name = models.OneToOneField(
Mainjoinbook,on_delete=models.CASCADE,primary_key=True,db_column='site_name'
)
latitude = models.TextField(blank=True,null=True)
longitude = models.TextField(blank=True,null=True)
class Meta:
managed = False
db_table = 'tblsiteaccess'