从 django 视图中的多个表中获取数据

Question

在 Django 视图中，我想获取任何特定 wid=1 的所有详细信息（Workeraccount.location、Workeravail.date、Workerprofile.*）。

SQL 查询：

select * from Workeraccount,Workeravail,Workerprofile where Workerprofile.wid=1 and Workerprofile.wid=Workeravail.wid and Workeraccount.wid=Workerprofile.wid;

对应型号如下：

class Workeraccount(models.Model):
    wid = models.ForeignKey('Workerprofile', db_column='wid', unique=True)
    location = models.ForeignKey(Location, db_column='location')
    class Meta:
        managed = False
        db_table = 'workerAccount'

class Workeravail(models.Model):
    wid = models.ForeignKey('Workerprofile', db_column='wid')
    date = models.DateField()
    class Meta:
        managed = False
        db_table = 'workerAvail'

class Workerprofile(models.Model):
    wid = models.SmallIntegerField(primary_key=True)
    fname = models.CharField(max_length=30)
    mname = models.CharField(max_length=30, blank=True, null=True)
    lname = models.CharField(max_length=30)
    gender = models.CharField(max_length=1)
    age = models.IntegerField()
    class Meta:
        managed = False
        db_table = 'workerProfile'`

Answer 1

以下是您只需一次数据库调用即可完成此操作的方法：

workprofile = Workerprofile.objects.get(pk=1)
    .select_related('workeravail_set', 'workerprofile_set')

这将一次性为您获取所有数据，然后可用于：

workprofile.workerprofile_set.location #Gets the Workeraccount.location
workprofile.workeravail_set.date       #Gets the Workeravail.date
workprofile.fname                      #Example of Workerprofile.*

顺便说一句，如果你想要一个比“*_set”方法更短的方法来引用外来对象，你可以设置一个related_name，比如

class Workeraccount(models.Model):
    wid = models.ForeignKey('Workerprofile', db_column='wid', unique=True, related_name='waccount')
    ...

然后将workeraccount_set替换为waccount

Answer 2

你可以这样做：

workprofile = Workerprofile.objects.filter(id=1).first()
all_worker_avails = workprofile.workeravail_set.all()
all_workeraccounts = workprofile.workeraccount_set.all()

由于Workeraccount 和Workeravail 通过Workerprofile 关联，您可以轻松获得一个查询集 - 您需要两个单独的查询集。

您还可以执行以下操作：

all_worker_avails = Workeravail.objects.filter(wid=workprofile)
...